CLO DRAFT submitted 03/27/2017

Cod Liver Oil – Back to the Future

Introduction

Cod liver oil (Gadus morhua [Linnaeus, 1758]) is a revered 8th century natural medicine that strengthens the body, relieves joint pain and treats skin problems. Cod liver oil’s reputation continued into the 21st century, and is experiencing a resurgence of interest within the scientific community (R. D. Semba, 2012). Several reasons for this renewal may be linked to cod liver oil’s unique constituent profile which affords meaningful levels of naturally occurring vitamins A (retinol), D3 (cholecalciferol), and the family of essential long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Cod liver oil’s composition can prevent multiple micronutrient deficiencies consistent with the United Nations Millennium Development Goals 2015 and Beyond. Additionally, consuming cod liver oil offers a safe and cost-effective way to ingest the nutritional benefits of seafood necessary to meet physical requirements for optimal health. Increasing the dietary status of vitamin D alone in Western Europe has been estimated to alleviate the economic burden of disease by $293 billion per year (Bengtson Nash, Schlabach, & Nichols, 2014). We find ourselves going back to the future to revisit the health benefits of this remarkable fish oil driven by economic and food resource pressures..

This paper delves into the story behind cod liver oil’s resurgence. It explores 1) cod liver oil’s impressive empirical record for treating a wide variety of complaints from skeletal problems to infections; 2) the scientific community’s exploration of potential synergistic relationships between cod liver oil’s key constituents; 3) new methods of minimally processing cod liver oil that preserve its “virgin” crude constituent profile while removing environmental contaminants; and, 4) an overview of cod liver oil’s contemporary clinical applications.

Cod Liver Oil – 8th through 21st CenturiesMarine liver oils have enjoyed a reputation as a health promoting food and therapeutic intervention for millennia by maritime cultures around the world. In 5th century BC Mediterranean culture, the Greek physician, Hippocrates, mentions using dolphin liver oil internally and topically for chronic skin eruptions. Earlier than the 8th century, ancestral fishing communities living on the shores of the Atlantic Ocean, North, Baltic and Norwegian Seas, are known to have used Atlantic cod liver oil (Gadus morhua [Linnaeus, 1758]) therapeutically in poultices, salves, and ointments as well as,

internally, as a strengthening tonic and remedy for joint complaints. Norwegian fisherman rubbed cod liver oil on their joints and muscles to ease soreness (Brockbank, 1904; Guy, 1923; Haywood, 2000; MarineBio Conservation Society).

In 1650, rickets, the softening and weakening of bones in children leading to lifelong bone deformity, was acknowledged as a disease by an esteemed Cambridge physician, Frances Glisson. This condition was so pervasive and crippling in 17th century British Isles that it was called “the English Disease.” The application of cod liver oil for rickets, was a welcome and gentle option to prevailing treatments that were painful, ineffective and incapacitating (DeLuca, 2014; Rajakumar, 2003; Rosenfeld, 1997).

In Glisson’s own words, he “…suggested treatments for rickets included: cautery, incisions to draw out bad humors, blistering, and ligature of soft wool around the limb

to retard the return of blood. For correction of bony deformities, Glisson proposed splinting and artificial suspension of the affected infant: ‘The artificial suspension of the body is performed by the help of an instrument cunningly made with swathing bands, first crossing the brest and coming under the armpits, then about the head and under the chin, then receiving the hands by two handles, so that it is a pleasure to see the child hanging pendulous in the air, and moved to and fro by the spectators. This kind of exercise is thought to be many waies conducible in this affect, for it helpeth to restore the crooked bones, to erect the bended joynts, and to lengthen the short stature of the body’ (Rajakumar, 2003).

The early 18th century witnessed Northern European infirmaries and apothecaries prescribing cod liver oil to patients suffering from rickets and rheumatism based on the oil’s observed success as a folk remedy. By 1770, cod liver oil was adopted into conventional practice as a therapeutic agent by British and Northern European physicians solely on clinical empiricism and without any satisfactory explanation accounting for its superiority. The English doctor Samuel Kay of the Manchester Infirmary was credited with being the first to introduce the internal medical use of cod liver oil. Dr. Thomas Percival and Robert Darbey, from the Manchester infirmary, chronicled its spectacular effects in the treatment of chronic rheumatism, and Percival reported their results to the Medical Society on October 7, 1782(Abler).

Cod liver oil’s healing properties were recognized as more than skeletal. ‘‘Whether the disease of rickets be in its most severe form, with swollen joints and crooked legs, or at its commencement, the cod liver oil will supersede every other means of cure’’ and ‘‘a case of inflammation of the eyelids and intolerance of light was cured within ten days

with cod liver oil as were several cases of conjunctivitis of the cornea’’ (Carpenter, 1998).

The relationship between rickets and increased susceptibility to colds, bronchitis, and pneumonia was a frequent observation. In 1845, Dr. Graham Bradshaw speaking to the British Royal Society of Physicians and Surgeons described the remarkable clinical effects he had witnessed in his patients that were administered cod liver oil. He broadened its use to include patients suffering from various forms of arthritis as well as improvement in patients with tuberculosis (Bradshaw, 1845). He later reported a series of case histories of these successes in papers that were published in the Provincial Medical and Surgical Journal. He indicated that he had learned of the value of cod liver oil from a Belgian colleague, Dr. A Burgraeve who had spent time in Norway and witnessed the medicinal effectiveness of cod liver oil (Bills, Massengale, HICKMAN, & GBAY, 1938; Toogood, 1846).

By the end of the 19th century, based on the durability of accumulating evidence, cod liver oil was generally accepted to include treatment for rickets and osteomalacia, generalized malnourishment, certain eye and skin conditions and infections (Rosenfeld, 1997) despite the scientific dogma that fats – whether from lard, butter, or cod-liver oil – were considered interchangeable in nutrition (R. Semba & Kramer, 2012).

Over the next 100 years ago, it became well recognized that cod liver oil was different from other types of marine, animal or vegetable oils in its healing properties. The evolving story of its profound versatile nature and increasing acceptance in medicine began with the emergence of the concept of “dietary deficiency diseases” in concert with the discovery and isolation of vitamins, specifically, vitamins A (retinol) and D3 (cholecalciferol), beginning in the early 20th century(DeLuca, 2014).

Clinical observation of vitamin deficiencies preceded their isolation, structural descriptions and synthesis. The appreciation of vitamin A’s contribution to cod liver oil’s effects on immunity, earning it the name the “anti-infective” vitamin, came before the recognition of vitamin D’s influence on bone development(R. Semba & Kramer, 2012; R. D. Semba, 1999). Largely through the influence of Sir Mellanby, in the UK. vitamin A, given as cod liver oil, underwent a period of intense clinical investigation. Between 1920 and 1940, at least 30 trials were conducted to determine whether vitamin A could reduce the morbidity and mortality from infectious diseases, including respiratory disease, measles, puerperal sepsis, and tuberculosis. By the 1930s, it was established that vitamin A supplementation could reduce morbidity and mortality in young children. Supplementation reduced the mortality of vitamin A-deficient children with measles by

nearly 60%. Vitamin A, given as cod liver oil, became a mainstream preventive measure; cod liver oil was part of the morning routine for millions of children and was acknowledged in saving the lives of children from poor families in England (R. D. Semba, 2012).

The unraveling of vitamin A and D in cod liver oil appears as an informal collaboration between Sir Mellanby in the UK and McCollum and colleagues in the United States. Concerned with the prevalence of rickets and intrigued by the work of McCollum eon vitamin A, Mellanby decided that rickets might be a dietary deficiency disease, a controversial concept at that time. In 1919, he used the diet consumed by the Scottish people (who had the highest incidence of rickets), primarily oatmeal, and fed that diet to dogs that he inadvertently kept indoors and away from sunlight. The dogs developed

rickets, which was identical to the human disease. Mellanby could cure the dog’s disease by providing cod liver oil, a standard of care at that time (Mellanby, 1988). He assumed that it was possible that recently discovered vitamin A in cod liver oil was responsible for the prevention of rickets (DeLuca, 2014; R. Semba & Kramer, 2012).

McCollum had been following Sir Mellanby’s finding, and decided to test the hypothesis of whether vitamin A was responsible for healing rickets. He bubbled oxygen through cod liver oil that destroyed vitamin A and found that this preparation was no longer able to prevent xerophthalmia (dry eyes), skin problems, weakened immune function and

other symptoms of vitamin A deficiency, but it still retained the ability to cure rickets.

McCollum and colleagues correctly concluded that the factor that cures rickets is a new vitamin, which they called vitamin D (DeLuca, 2014). The European medical community adopted the use of cod liver oil earlier than the United States. Perhaps this is because of Europe’s proximity to Scandinavia, exposure to Norse folklore and the availability of cod liver oil.

In the United States, from the 1920s through the 1950s, the British regimen of daily cod liver oil use was adopted by physicians and endorsed by the US Government. Supplementation began when infants were only a few months old. Cod liver oil was used for tuberculosis and other ‘‘wasting’’ diseases (Linday, 2010).

While rickets was rampant among poor children living in the industrialized and polluted northern cities in the United States, the value of cod liver oil was largely dismissed as a folk medicine. By the 1930s, only after the discovery of vitamin D, and the delineation of the anti-rachitic properties of cod liver oil, did it become possible to not only treat but also eradicate rickets in the United States. Cod liver oil became an indispensable part of

every child’s diet (Rajakumar, 2003).

Cod-liver oil represented a whole food source of two “new” essential nutrients with demonstrated significant healing benefits: vitamin A for growth, healthy eyes and immune function and vitamin D for proper bone development (R. D. Semba, 2012).

The unfolding of cod liver oil’s unique active principles does not end with vitamins A and D. In the late 20th century, it continues with the identification of a class of fats known as essential long-chain omega-3 polyunsaturated fatty acids (ω3FA) found in cod liver oil. In 1978, J Dyerberg and Bang (1978) reported that the incidence of myocardial infarction was very low in Greenland Eskimos whose diet consisted of marine lipids rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (J Dyerberg & Bang, 1978; Spector & Kim, 2015).

The age of chemistry ushered in the ability to partition foods, isolate and synthesize their discrete molecules. The emerging fields of biotechnology, molecular biochemistry and nutrigenomics are rapidly advancing our understanding of how food and its derivatives interact with our genome to make marked changes in gene expression for better or worse (Subbiah, 2008). This “omics” revolution explores how food-specific molecules influence cellular communication which can substantially effect our quality of life and longevity. On the other hand, this new research directive supports food fortification and reinforces the use of isolated nutrients and engineered supplements over whole food extracts and concentrates.

In the case of cod liver oil, vitamins A, D and ω3FA taken alone or in combination have become the preferred bio-actives over consuming cod liver oil, the parent that supplies all three. While there is a large body of evidence on the benefits of the individual nutrients (Table 1), cod liver oil’s place in the dietary supplement and therapeutic decision tree warrants clarification owing to its remarkable history for the treatment for inflammation, immune and bone disorders.

Cod Liver Oil – Exploring Synergy

Synergy is defined as the interaction of constituents that when combined produce a total effect that is greater than the sum of the individual elements. Synergism between elements may contribute to an array of benefits. With the understanding that the complete composition and biochemical complexity of crude cod liver oil is yet to be revealed, naturally occurring vitamin A, D3 and ω3FA appear to be working in tandem.

Table 2 provides a cod liver oil constituent profile showing comparisons to the Recommended Daily Allowance (RDA and Tolerable Upper Intake Level (UL) for isolated Vitamins A and D3; and the Global Recommendations for ω3FA, EPA and DHA Intake (GOED). Knowledge of naturally occurring levels of these key nutrients in a minimally processed and standardized cod liver oil may explain early experiences with cod liver oil, both negative and positive, and open discussion to how these naturally occurring nutrients mutually support one another, enhancing their effectiveness and bioavailability at lower doses.

Vitamins A, D and Omega 3 Fatty Acid Interdependency

Current molecular biology has established vitamins A, D and ω3FAs as essential contributors to health across the lifespan. These nutrients are also critical as nutritional support for a number chronic health conditions (Table 1). Vitamin A plays a pivotal role as essential for vision, embryonic development, normal growth and development of infants, and immunity (Chelstowska, Widjaja-Adhi, Silvaroli, & Golczak, 2016). Vitamin D has roles in a variety of biological actions such as calcium homeostasis, cell proliferation, and cell differentiation to many target tissues. The extra-skeletal importance of vitamin D has been shown to reduce the risk of chronic diseases including autoimmune diseases, common cancer and cardiovascular disease(Holick, 2009). The actions of vitamin A and D are now thought to be exerted through the vitamin D receptor (VDR) and vitamin A receptor (RAR) by their metabolites, the active hormone D, 1,25-Dihydroxvitamin D3 ([1,25(OH)2D) and retinoic acid (RA)(Christakos, Dhawan, Verstuyf, Verlinden, &

Carmeliet, 2016). Accumulating research on ω3FA suggests that these dietary essential lipids modulate numerous processes, including brain and visual development, inflammatory reactions, thrombosis and carcinogenesis (Surette, 2008). The number of shared pathways and genomic interdependence strongly suggests synergy and explains, in part, the willingness of the medical community to accept cod liver oil based on clinical empiricism.

Vitamins A and D Intimate Partners in Health

The biochemical basis for synergy between vitamins A and D began in the 1930s and continued through the 1960s. Early research suggested that vitamins A and D protected against the toxicity of the other (Clark & Smith, 1964). Developments in molecular biology show the metabolite of vitamin A, retinoic acid (RA), and the hormonally active form of vitamin D, 1,25-Dihydroxvitamin D3 [1,25(OH)D] produced enzymatically, are

mediated through their vitamin A (RAR) and vitamin D (VDR) receptors. Retinoic acid

and activated D share most of their actions by binding to the same nuclear receptor called the retinoic acid-vitamin D receptor (RXR-VDR) heterodimer which also includes receptors for thyroid hormone, sex hormones, and adrenal steroids. This shared receptor binding brings RA and 1,25(OH)D into contact with DNA inside the nucleus of

the cell enabling the modulation of gene expression in numerous parts of the body (Christakos et al., 2016). Recent research, has shown that vitamin D can only effectively control the expression of genes in the presence of vitamin A (Sánchez Martínez, Castillo,‐ Steinmeyer, & Aranda, 2006).

Recently, in a diverse cohort of HIV-infected adults from predominantly low- and middle-income countries, deficiencies in vitamin A and vitamin D at anti-retroviral (ART) initiation were independently associated with increased risk of incident tuberculosis (TB) in the ensuing 96 weeks. The researchers concluded that Vitamin A and D may be important modifiable risk factors for TB in high-risk HIV infected patients starting ART in resource-limited, highly-TB-endemic settings (Tenforde et al., 2017).

Omega-3 Polyunsaturated Fatty Acids and active Vitamin D [1,25(OH)D]

In the past number of years, the anticancer activities of omega-3 polyunsaturated fatty acids as well as vitamin D have been intensively studied, but separately. Dyck, Ma, and Meckling (2011) explored the theoretical argument that cod liver oil, one of the few natural product sources for both molecules, may possess additive and possibly synergistic anticancer effects. Mechanisms of action were related to the shared anti-inflammatory, pro-apoptotic, anti-angiogenic and anti-proliferative pathways between omega-3 and vitamin D (Dyck et al., 2011). While vitamin A was not discussed, research points to the interdependence of vitamin A and D metabolites, and the possible dependency of vitamin D receptor expression on retinoic acid via the XRX-VDR nuclear receptor.

Cod Liver Oil and Enhanced Absorption

The complete profile of cod liver oil is more than vitamins A, D and ω3FA. Omega-3 fatty acids in cod liver oil have been shown to afford better digestibility and absorbability in their triglyceride (TG) form than the more purified ω3FA ethyl ester form (Jørn Dyerberg, Madsen, Møller, Aardestrup, & Schmidt, 2010). Also, present in cod liver oil are substances termed phospholipids, known to be building blocks for the development of the nerves, eyes and brain. Phospholipids have been found to work with omega-3 oils to support healthy immune, nervous, liver, and blood vessel functions (Burri, Hoem,

Banni, & Berge, 2012). Animal and human studies suggest that phospholipids further enhance the bioavailability of omega-3 oils (Bengtson Nash et al., 2014; Burri et al., 2012; Liisberg et al., 2016).

Bioavailability and synergy research utilizing cod liver oil, in humans of varying ages, gender and ethnicity, will begin to unravel the question whether consuming minimally processed “virgin” cod liver oil will have a sparing effect on each of the components and provide comparable health benefits when taken daily as a dietary or for more serious conditions (Table 1).

For example, as a food supplement, vitamin A use is limited to the upper tolerable limit of 10,000 IU for adults, a level easily achieved by consuming 4 teaspoons daily (Table 2). This amount of cod liver oil is associated with therapeutic benefits historically. Contrast taking 10000 IU vitamin A daily from cod liver oil to boost immune function to taking isolated vitamin A. Doses range between 20,000 to 400,000 IU prescribed in a variety of regimens. Routines fluctuate between daily and intermittent use and single dose therapies. Interestingly, these routines are for a variety of clinical conditions akin to the empirical usage of cod liver oil - improve immune functions, night blindness, prevent and treat vitamin A deficiency, skin conditions including eczema, psoriasis, keratosis follicularis and ichthyosis, various cancers, infectious disease and prevent infant mortality. Individual responses are carefully monitored based on over all and liver health (Mayo Clinic, 2017).

Cod liver oil research in the areas that overlap with the use of vitamins A, D and ω3FA as single interventions are ongoing for serious health conditions. Synergies may occur due to vitamin A’s intimate molecular role supporting the expression of vitamin D and vitamin D’s relationship to modulating the immune and endocrine systems. Additionally, the ω3FA may further enhance immune function by managing inflammatory messaging. Other possible synergies may be related to the ratios of vitamin A, D and ω3FA and their collaboration with phospholipids, additional bio-actives, and the improved absorption of the TG form ω3FA. What we do know is that cod liver oil is a safe and effective way to nourish the skin, eyes, immune, endocrine, cardiovascular and neurological systems.

Cod Liver Oil – Vitamin A Enigma

During the 1920s through 1950, the cod liver oil prescribing practices of physicians were liberal. Clinical success was associated with typical regimen of between 1 and 4 teaspoons of cod liver oil daily for infants and children for healthy bone development, measles and many types of upper respiratory conditions. Adults were prescribed cod liver oil similarly (Linday, Umhau, Shindledecker, Dolitsky, & Holick, 2010). Assuming a

cod liver oil constituent profile like that presented in Table 2, four teaspoons were safe for adults and children over 3 years. Infants and children 3 years or less, were at risk to vitamin A over exposure if intake was not connected with an illness. Four teaspoons would provide approximately 10,000 IU of vitamin A, the upper tolerable limit (UL) for adults. Children, 3 years and below, the UL is 2,000 IUs. Vitamin A intake for healthy children was five times greater than recommended.

The safety concerns regarding vitamin A are tied to how it is stored and metabolized. Embryonic development is orchestrated by a small number of signaling pathways, one of which is the retinoic acid (RA) signaling pathway, and vitamin A is the molecular precursor of the essential signaling molecule RA. The level and distribution of RA signaling within a developing embryo must be tightly regulated; too much, or too little, or abnormal distribution, all disrupt embryonic development (Metzler & Sandell, 2016). Retinoic acid, alone, can enhance or decrease expression of more than 500 genes depending on the target cell type and the physiological state of the organism (Chelstowska et al., 2016). For all these reasons, appropriate levels of vitamin A became a concern for infants, children under 3 years, and, especially, during pregnancy and lactation. Use of properly labeled and prepared cod liver oil as a food supplement resolves this safety dilemma.

Table 1. Health Benefits and Clinical Associations

Cod Liver Oil 8th Century: in poultices, salves, and ointments; internally, as a strengthening tonic and remedy for joint complaints

18th Century: rickets and rheumatism, eye complaints, “wasting disease”

19th Century: used to treat tuberculosis, rickets, malnourishment, osteomalacia (softening of the bones in adults), and some eye conditions, arthritis (Brockbank, 1904; Guy, 1923; Rosenfeld, 1997)

20th Century 1920-1940: Used both as a prophylactic and intervention to reduce the morbidity and mortality of respiratory disease, measles, puerperal sepsis in children and adults (R. D. Semba, 1999). Used to treat rickets and osteomalacia in both children and adults

21st Century: reduce cardiometabolic risk factors, have anticancer effects, and ameliorate cognitive impairment induced by chronic stress, potential beneficial effects in preventing the progression of glaucoma (Huang, Fan, & Zhang, 2011)

Vitamin A (retinol) Essential for proper immune function, epithelial growth and repair,

Vitamin A (retinyl palmitate) bone growth, reproduction, and normal embryonic and fetal development. improvea immune functions, night blindness, prevent and treat vitamin A deficiency, skin conditions including eczema, psoriasis, keratosis follicularis and ichthyosis, various cancers, infectious disease and prevent infant mortality (Mayoclininc.org)

D2

(ergocalciferol)

D3

(cholecalciferol)

Activated vitamin D via hepatic enzymatic hydrolysis influences the body through the vitamin D receptor (VDR). There are as many as 500–1000 genes may be regulated by VDR ligands that control various cellular functions including growth, differentiation, and apoptosis (Reichrath, Zouboulis, Vogt, & Holick, 2016). Distribution of VDR throughout the skeletal, endocrine and immune systems link vitamin D status and its transformation to multiple health conditions. Those for which the benefits are well supported and have large economic effects include many types of cancer, cardiovascular diseases, diabetes mellitus, several bacterial and viral infections and autoimmune diseases such as multiple sclerosis (Grant et al., 2009; Gröber, Reichrath, & Holick, 2015).

Long chain omega-3 unsaturated fatty acids - eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA

Modulate numerous processes, including brain and visual development, inflammatory reactions, thrombosis and carcinogenesis. Inflammatory modulations: dietary omega-3 fatty acids directly affect arachidonic acid metabolism because they displace arachidonic acid from membranes and compete with arachidonic acid for the enzymes that catalyze the biosynthesis of thromboxanes, prostaglandins and leukotrienes. The net effect of consuming foods enriched in omega-3 fatty acids is a diminished potential for cells like monocytes, neutrophils and eosinophils to synthesize these powerful arachidonic acid–derived mediators of inflammation and a diminished potential for platelets to produce the prothrombotic agent thromboxane A2 (Jiang et al., 2016;

Surette, 2008).

Table 2. Virgin Cod Liver Oil1 Constituent Profile2 Compared to RDA/UL for Individual Components – Vitamins A, D and Omega-3 Fatty Acids (EPA and DHA)

Virgin Cod Liver Oil Minimally Processed Constituent Profile ~ 4,500 mg (5ml or 1 tsp)1,2

RDA Daily Dosing Ranges by Age for isolated nutrients4

UL Daily Dosing Ranges by Age for isolated nutrients5

Total Omega-3s (as naturally occurring TG)3 950 -1000 mg

Not available: Refer to Global Recommendations for EPA and DHA Intake (Rev 16 April 2004)6

USDA: 3 grams/d because of possible adverse effects related to glycemic control, increased bleeding tendencies and elevations in low-density lipoprotein

cholesterol associated with very high intake of omega-3 fatty acids. Whether these concerns are warranted remains to be determined; however, it is not clear if these higher doses would provide additional health benefits (Surette, 2008).

EPA (naturally occurring TG) 418 - 440 mg

Purdent daily intake: 250 mg – 1.0 grams/day

DHA (naturally occurring TG) 380 - 400 mg

Purdent daily intake: 200 mg -1.0 gram/day

Vitamin D3 (naturally occurring cholecalciferol) 188 - 200 IU

0-12 mo: – 400 IU

1-70: – 600 IU

>70: – 800 IU

Pregnancy - 600 IU

Lactation - 600 IU

9-70 yrs - 4000 IU

>70 - 4000 IU

Pregnancy - 4000 IU

Lactation - 4000 IU

Vitamin A (naturally occurring retinol)

2160 - 2400 IU 0-6 mo: 1,300 IU

7-12 mo: 1700 IU

1-3: 1000 IU

4-8: 1300 IU

9-13: 2000 IU

14-18: 3000 IU (m) 2,300 IU (f)

19-50+: 3000 IU (m) 2300 IU (f)

Pregnancy 14-18: 2500 IU 19-50: 2560 IU

Lactation 14-18: 4000 IU 19-50: 4300 IU

0-12 mo: 2000 IU

1–3: 2000 IU

4 – 8: 3000 IU

9–13: 5,666 IU

14–18: 9,333 IU

19-50+: 10,000 IU

Pregnancy 14-18: 9,333IU 19-50: 10000 IU

Lactation 14-18: 9,333 IU 19-50: 10000 IU

Alaskan cod (Gadus macroencephalus)1, Marine Ingredients2, Measured as Triglyceride (TG)3

Recommended Daily Allowance (RDA) https://ods.od.nih.gov/factsheets. Tolerable Upper Intake Level (UL): Dietary Reference Intake Tables and Application from Institute of Medicine of the National Academy of Sciences, November 30 20105 Global Recommendations for EPA and DHA Intake (Rev 16 April 2014)6

Virgin Cod Liver Oil – From Sea to Shelf

Cod liver oil’s clinical reputation is tethered to the crude oil constituent profile used traditionally. Only careful harvesting, processing and storage can promise to deliver the benefits of a full-spectrum, contaminant-free cod liver oil. To insure cod liver oil quality and bioactivity, chain of custody documentation along the supply chain and transparency are critical to detecting fish substitutions, contamination, freshness, ingredient claims or mislabeling.

The important criteria for selecting a cod liver oil that provide the health promoting bioactive immune factors are: 1) sourced from waters low in environmental toxins and pollutants, 2) sourced from sustainable fisheries that deliver reproducible nutrient and quality cod, 3) quickly processed at point of harvest at lower temperatures to preserve the heat sensitive full spectrum of nutrients and fatty acids, 4) extraction and distillation methods demonstrated to consistently preserve the “virgin” constituent profile batch after batch, and 5) a post-production certificate of analysis verifying nutrient level claims and freedom of toxicants.

The Waters Where Cod Swim

There are two species of cod, Atlantic (Gadus morhua) and Alaska/Pacific (Gadus macrocephala). Both possess rich profiles of vitamin A, D and omega-3 fatty acids in varying ratios with traces of naturally occurring bio-active molecules known to have positive health benefits. Of the two species, Alaska cod swim in the cleanest waters. All Alaskan fish species tested have either non-detectible or very low concentrations of persistent organic pollutants (POPs). No POPs were detected at levels of health concern in any fish species tested, and no limitations in Alaska fish consumption are warranted or recommended. Levels of toxic metals like methyl mercury are also found to be insignificant in Alaskan cod.

Persistent organic pollutants (Table 3) act as powerful pesticides and serve a range of industrial purposes. Some POPs are also released as unintended by-products of combustion and industrial processes. While the risk level varies from POP to POP, all these chemicals share four properties: 1) they are highly toxic; 2) they are persistent, lasting for years or even decades before degrading into less dangerous forms; 3) they evaporate and travel long distances through the air and through water; and 4) they accumulate in fatty tissue.

POP attraction to fatty tissue, known as "bioaccumulation", means that even though a poison is first dispersed widely and thinly it gradually starts to concentrate as organisms consume other organisms as they move up the food chain. Adverse health effects associated with POPs exposure may include hormone disruption, effects on learning and behavior, immune system suppression, and cancer. During pregnancy and breastfeeding these POPs are often passed on to the next generation. Human beings and other mammals are thus exposed to the highest levels of these contaminants when they are most vulnerable – in the womb and during infancy, when their bodies, brains, nervous systems, and immune systems are in the delicate process of construction (Interim Secretariat of the Stockholm Convention and UNEP's Information Unit for Conventions, 2002).

In comparison, Atlantic cod populations do not enjoy the reputation of Alaskan. Atlantic cod populations are currently believed to be low and strict management measures have been implemented to rebuild the population. This East Coast fishery is highly regulated and fishing is restricted to ensure sustainability. Some Atlantic cod is farmed(Jobling & Leknes, 2010). Pacific cod is considered healthy and abundant throughout its range and not subject to overfishing. Per the National Marine Fisheries Service, Pacific Cod is “hailed as being one of the best managed fisheries in the world” (Alaska Department of Health and Social Services, 2016).

Table 3. The First 12 POPs1ß

Aldrin A pesticide applied to soils to kill termites, grasshoppers, corn rootworm, and other insect pests.

Chlordane Used extensively to control termites and as a broad-spectrum insecticide on a range of agricultural crops

DDT Perhaps the best known of the POPs, DDT was widely used during World War II to protect soldiers and civilians from malaria, typhus, and other diseases spread by insects. It continues to be applied against mosquitoes in several countries to control malaria.

Dieldrin Used principally to control termites and textile pests, dieldrin has also been used to control insect-borne diseases and insects living in agricultural soils.

Dioxins These chemicals are produced unintentionally due to incomplete combustion, as well as during the manufacture of certain pesticides and other chemicals. In addition, certain kinds of metal recycling and pulp and paper bleaching can release dioxins. Dioxins have also been found in automobile exhaust, tobacco smoke and wood and coal smoke.

Endrin This insecticide is sprayed on the leaves of crops such as cotton and grains. It is also used to control mice, voles and other rodents.

Furans These compounds are produced unintentionally from the same processes that release dioxins, and they are also found in commercial mixtures of PCBs.

Heptachlor Primarily employed to kill soil insects and termites, heptachlor has also been used more widely to kill cotton insects, grasshoppers, other crop pests, and malaria-carrying mosquitoes.

Hexachlorobenzene (HCB)

HCB kills fungi that affect food crops. It is also released as a byproduct during the manufacture of certain chemicals and as a result of the processes that give rise to dioxins and furans.

Mirex This insecticide is applied mainly to combat fire ants and other types of ants and termites. It has also been used as a fire retardant in plastics, rubber, and electrical goods.

Polychlorinated Biphenyls (PCBs)

These compounds are employed in industry as heat exchange fluids, in electric transformers and capacitors, and as additives in paint, carbonless copy paper, sealants and plastics.

Toxaphene This insecticide, also called camphechlor, is applied to cotton, cereal grains, fruits, nuts, and vegetables. It has also been used to control ticks and mites in live- stock.

United Nations Environmental Program (UNEP) Published by the United Nations Environment Programme in August 2002. Produced by the Interim Secretariat of the Stockholm Convention and UNEP’s Information Unit for Conventions.

Sustainable, Wild, Line-caught Cod – Key Features of Biologically Active Cod Liver Oil

Insuring that cod liver oil is manufactured from sustainable, wild cod populations is a critical part of the process that guarantees the cod liver will possess a similar biochemical complexity to the cod associated with the health and medicinal benefits of traditional preparations.

A fishery that practices sustainability, regardless of location, means they are harvesting their catch at a level that allows wild fish to remain healthy and productive into the future. Not only do sustainability practices allow fish populations to thrive, fishing operations are managed to maintain the structure, productivity, function and diversity of the ecosystem on which the fishery depends. This includes protecting the habitat and associated dependent and ecologically related species of marine mammals, birds and plant life. Further, to be called “sustainable,” a fisher meets all local, national and international laws and has a management system in place to respond to changing circumstances to maintain sustainability (Marine Stewardship Council, 2016).

How the cod is caught and handled at the moment of harvest are other key determinants of raw material quality. Historically, cod was processed very near the time it was caught to avoid the oil from becoming rancid. Today we understand the importance of timing because of the cod liver’s unique enzymatic activity and ability to auto-digest itself once the cod has been killed. Managing the auto-digestion process is accomplished by immediately removing and flash freezing the cod’s liver upon their death.

Table 4 describes numerous ways to harvest cod that are associated with sustainability. The preferred capture method, however, for procuring cod livers destined for dietary supplement and medicinal use is the pole-and-line method because it prevents the crowding of cod which damages their internal organs.

When line-caught is combined with flash freezing, degradation is prevented. When the frozen cod livers arrive for processing, their freshness is assured. Adherence to this process is more critical for cod liver oil than any other type of marine lipid concentrate. Other marine lipids concentrate a limited number of bio-actives from the entire fish body. The cod liver harvesting targets the preservation of a wider spectrum of bio-actives and their delicate ratios.

Table 4. Cod Fishing Methods Pole/Troll Use a pole-and-line and bait to target a variety of fish ranging from

open-ocean swimmers, like tuna and mahi mahi, to bottom-dwellers, like cod.

Very low bycatch rates because fishermen catch one fish at a time and can release unwanted species when they're caught.

Trolling Hook-and-line method of fishing tows lines behind or alongside a boat, catching species, such as salmon, mahi mahi and albacore tuna, that follow a moving lure or bait.

Can quickly release unwanted catch from their hooks since lines are reeled in soon after a fish takes the bait.

Very low bycatch levels.

Bottom Trawl Type of fishing net that's pulled along the seafloor. Commonly used to catch shrimp and bottom-dwelling fish like halibut and sole.

Catches a variety of ocean life that's usually thrown back dead or dying. Dragging heavy gear across the seabed can also damage sensitive

seafloor habitat. The harmful effects of bottom trawling on bottom-dwelling organisms

and their habitat can be reduced by modifying the fishing gear or limiting trawling areas.

Handlines and Jigs Handlines are handheld gears that have low bycatch of other Use natural or artificial bait on hooks to lure fish. The fishing line may be attached to a pole or rod. When used in deep

waters, handlines are usually reeled in mechanically.

A jig is a type of grapnel (or grappling hook) that's attached to a fishing line.

Involves manually or mechanically moving the jig in the water to lure prey, and then quickly pulling or jerking the fishing line to hook fish.

Usually done at night with lights to lure fish and squid closer to the surface.

Gillnetting Uses curtains of netting that are suspended by a system of floats and weights

Can be anchored to the seafloor or allowed to float at the surface.

Netting is almost invisible to fish, so they swim right into it.

Often used to catch sardines, salmon and cod

Can accidentally entangle and kill other animals, including sharks and sea turtles.

Longlining A central fishing line that can range from one to 50 miles long Line is strung with smaller lines of baited hooks, dangling at evenly

spaced intervals. Can be set near the surface to catch pelagic fish like tuna and swordfish,

or laid on the seafloor to catch deep-dwelling fish like cod and halibut. Many lines can hook sea turtles, sharks and seabirds that are also

attracted to the bait. By sinking longlines deeper or using different hooks, fishermen can

reduce the bycatch problem.

Midwater Trawlers Vary in size—from small ships to large factory vessels. Large industrial ships pull gigantic nets through the open ocean and can catch an entire school of fish—spanning the size of five football fields—at once.Trawls don't impact the seafloor when used in the midwater zone.Setting these trawls on schooling fish using streamer lines to scare away seabirds and avoiding areas with an abundance of marine mammals can help ensure low levels of bycatch in midwater trawl fisheries.

Monterey Bay Aquarium Seafood Watch (2017)

Cod Liver Oil Biological Activity – the Process Defines the Product

The many health benefits of eating fish and their derivatives are well established. These benefits are also associated with the specific fish, fish part and quantity consumed. Cod liver oil is different than other marine oils. It offers the rare opportunity to ingest significant to therapeutic levels of naturally occurring vitamins A, D, omega-3 fatty acids and additional immune enhancing bio-actives specific to cod liver. Using properly refined cod liver oil complements eating fish, reduces the dependency on finding local

clean fish for meals and resolves any concerns surrounding exposure to unwanted environmental pollutants associated with increased fish consumption.

The cleaner the cod livers prior to refining and concentration, like those livers in Alaska cod, the less exposure to higher temperatures and tampering required to remove toxicants, off-taste and odor and oxidants and fatty acids that cause the oil to become cloudy upon cooling. In summary, there is less degradation and loss of labile bio-actives like vitamins A and D and their congeners, and the more sensitive phospholipids (Gillam, 1938). Clean livers require minimal-processing. The finished product does not require augmentation with additional nutritional factors like vitamins A and/or D to approximate the virgin profile.

The molecular biochemistry of cod liver oil is not defined by its vitamin A, D and omega-3 fatty acids content alone. The identification and importance of maintaining all the unique properties of intact cod liver oil is a work in progress. Based on traditional use, the prevailing assumption is that minimally-processing cod liver oil will tend to preserve the profile of the virgin oil and afford greater potential for the oil to express its multi-dimensional activity. Currently, to produce Atlantic cod liver oil, farmed or wild, that meets the World Health Organization’s allowable toxicity levels (see Table 6), the finished product requires the reintroduction of one or more of the key nutrients – vitamins A, D or omega-3 fatty acids.

Figure 1 compares finished product levels of Alaska to Atlantic cod liver oil vitamin A content. Alaska cod liver oil vitamin A occurs with its vitamin A congeners (metabolites). The Atlantic cod liver oil contains vitamin A palmitate, a synthetic vitamin A, re-introduced post-processing. While the clinical value of vitamin A congeners is not known, these metabolites, at the very least, represent biomarkers of processing sensitivity. Their presence may be associated with other trace amounts of bio-actives that collectively contribute to a more robust oil.

Figure 1. Biomarkers of Sensitivity - Vitamin A Congeners

Alaska Cod

Atlantic Cod

Cod Liver Oil – Post-Production Certificate of Analysis

Cod liver oil’s performance in the clinic and as a food supplement is dependent on its demonstrated constituent profile batch after batch after batch. A certificate of analysis (COA) is one guarantee of potency, purity and freshness (Table 6) that is mandatory to support product confidence. Typically, the major constituents in cod liver oil, vitamins A and D with total omega-3 fatty acids including EPA and DHA, and their amounts per serving, will be listed in the COA. Accompanying these nutrition values are indicators of freshness (peroxide and anisidine) and purity. Purity is reflected by environmental pollutant and toxic metal exposure (PCBs, Dioxins, Furans. mercury, lead, arsenic, cadmium.)

The other guarantee of potency, not on the COA, measures, post-processing, the preservation of other delicate bio-actives that reflect the complexity of virgin cod liver oil. These components, like the vitamin A congeners, are sensitivity biomarkers. A manufacturer concerned about producing a minimally-processed oil, will develop a method for measuring bio-markers that reflect a full-spectrum finished product. While these bio-markers may not be on a COA, they would be available upon request.

What remains unclear is the impact that using highly refined cod liver oil has on its health benefits and clinical application. The assumption that the benefits of cod liver oil are limited to vitamins A and D and omega-3 essential fatty acids supports using

degraded material and ignores what may be lost by disrupting the natural balance and synergy between all the existing components in the oil.

Table 6. Alaska Cod Oil Typical Certificate of Analysis

Current Clinical Evidence of Cod Liver Oil’s Efficacy

Clinic evidence for the efficacy of cod liver oil (CLO) is not as robust as the epidemiological research that aligns with historical uses. Here we address an array of conditions where CLO shows promise in decreasing disease risk, and managing symptoms. These current clinical applications of CLO leverage the wide body of nutrigenomic research related to its major components - vitamins A, D and omega-3 fatty acids. The following studies are limited to exploring CLO as nutritional support for cancer (M. Brustad, Braaten, & Lund, 2003), depression (Raeder, Steen, Vollset, & Bjelland, 2007), rheumatoid arthritis (Galarraga et al., 2008; Kumar Gupta, Khan Zafer, & Ahmad, 2013) and multiple sclerosis (Cortese et al., 2015). Worth noting is that this research uses highly refined fortified Atlantic cod liver oil varying in composition.

Cod liver oil as nutritional adjuvant for cancerThe European Prospective Investigation into Cancer and Nutrition (EPIC) was a sample of 37,226 women age 41-55 years (M. Brustad et al., 2003). M. Brustad et al. (2003) used this cohort to assess CLO supplementation use. They found that those with an overall healthy lifestyle were more likely to use CLO. Vitamin D is addressed as an important constituent in CLO. However it was concluded that CLO use did not match the Vitamin D needs of the cohort (M. Brustad et al., 2003). Furthering the discussion of lifestyle - Mølje , a traditional Norwegian dish was served to a population of thirty-three volunteers to see if it had an acute effect on 25-hydroxy vitamin D (25[OH]D) blood concentration at 4-hours, 12-hours, and 5-days following the meal (M. Brustad et al., 2003). The elements of Mølje that were given credit for potential acute increases were cod liver and cod-liver oil. As illustrated in Table 7, the single meal did not show increases in 25(OH)D at the post meal time intervals. It is important to note for the scope of this paper that the authors did track the participants that were supplementing with cod liver oil. Their observations indicated that those who did not supplement with CLO were below the recommended levels of 25(OH)D blood concentrations.

Cod liver oil and depressionThe study conducted by Raeder et al. (2007) was a follow up to the Hordaland epidemiological study of Hordaland County in Norway. As previously stated CLO has been used for centuries for a wide array of conditions. A portion of the questionnaire circulated during the Hordaland study used the Hospital Anxiety and Depression Scale to provide a quantitative analysis of depressive and anxiety symptoms. The results were divided into CLO users and Non-CLO users. There was a significant association between CLO usage and lower levels of depressive symptoms when compared to the non-CLO users (P=0.032).

Cod liver oil and rheumatoid arthritis (RA)Symptoms of rheumatoid arthritis (RA) are often managed by non-steroidal anti-inflammatory drugs (NSAIDs) which are associated with negative side effects that hinder quality of life. Given the high levels of naturally occurring omega-3 fatty acids in cod liver oil, it is suggested that the natural anti-inflammatory properties of these essential fatty acids could potentially reduce the dependency on NSAIDs in the RA population (Galarraga et al., 2008; Kumar Gupta et al., 2013). A longitudinal open labeled study performed by Kumar Gupta et al. (2013) explored the effects of CLO on rheumatoid arthritis (RA) by looking at three dependent variables (refer to Table 7 for outcome measures and CLO dose.) The purpose of the study was to assess the efficacy of CLO on reducing daily dose of Diclofenac Sodium with the intention of reducing the risk of side

effects associated with this NSAID. There was a significant reduction in the mean daily Diclofenac Sodium dose from week 4 to week 24 of the study. Pain reduced significantly based on the Visual Analog Scale and Subject Responses of “Better” from patients. Similar observations in reduction in NSAID dependence was also observed by Galarraga et al. (2008).

Cod liver oil and multiple sclerosis (MS)Cod-liver oil supplementation from ages 13-18 is potentially effective at reducing the risk of adult onset multiple sclerosis (MS) (Cortese et al., 2015). It was observed that a Vitamin D dose of 200-400 IU per day via CLO was effective at reducing the risk of adult onset MS for the adolescent population. However, for children under 13 and adults over 18, this was not supported (Cortese et al., 2015). Details of the study are presented in Table 3. The referenced effective daily dose of Vitamin D is established well supported (Magritt Brustad, Sandanger, Wilsgaard, Aksnes, & Lund, 2003; Raeder et al., 2007). Cortese et al. (2015) elaborate on their findings by suggesting that the other constituents of CLO could potentially enhance the effectiveness it’s use as a supplementation in relation to decreasing risk of MS, however it is acknowledged that this is not conclusive.

Table 7. Cod Liver Oil (CLO) Clinical StudiesStudy Subject Intervention Outcome

Measure(s)Significant Findings

(M. Brustad et al., 2003) Cross-sectional study

EPIC cohort –women age 41-55 yrs (n=37,226)

Sociodemographic CLO use

Blood concentration levels of vitamin D levels of the female population that supplement with CLO

CLO use is associated with healthy lifestyle habits. CLO supplementation did not increase Vitamin D levels

(Magritt Brustad et al., 2003) Non-clinical controlled trial

Volunteers from Tromsø, Norway (n=33)

Norwegian dish Mølje – cod, hard roe, cod liver (mean intake = 113.6 g, 100 g liver = 125 𝜇g (5000 IU)

Vitamin D, fresh cod-liver oil (mean intake = 20.8, 100 g CLO = 261 𝜇g (8640 IU)

25(OH)D blood concentration at 4-hours, 12-hours, and 5-days post meal

A single Mølje meal did not significantly increase 25(OH)D blood concentration at any time point. Population not supplementing with CLO had blood 25(OH)D concentration levels below recommended.

Vitamin D

(Raeder et al., 2007): Cross-sectional survey

Individuals in Hordaland County, Norway, ages 40-49 and 70-74(n=21,835)

Self-prescribed CLO for 12-monthsDHA – 0.3-0.6 gEPA – 0.3-0.6 gVit A – 250 𝜇gVit D – 10 𝜇gVit E – 10 𝜇g

HADS ScoreHigh levels of depressive symptoms = HADS-D score ≥ 8 and HADS-A score < 8High levels of anxiety symptoms = HADS-A score ≥ 8 and HADS-D score < 8

Decreased risk of high levels of depressive symptoms in CLO users compared to non-CLO users (P=0.032)

(Galarraga et al., 2008): Duel-center double-blind placebo controlled 9-month study

Rheumatoid Arthritis patients (n=97)

CLO 10 g (2.2 g n-3 EFAs)Placebo – air-filled identical capsule

Reduction in daily NSAID requirement by >30% after 9-months.

39% of the CLO group and 10% of the placebo group reduced daily NSAID requirement by >30% (P=0.002)

(Kumar Gupta et al., 2013): Longitudinal open labeled study

Rheumatoid Arthritis patients age 19-60 years (n=30)

5 CLO caps 2X daily.Per cap (daily dose total)CLO – 300 mg (3,000 mg)EPA – 20 mg (200 mg)DHA – 30 mg (300 mg)NSAID – DCNa 50 mg single dose to max 200 mg per day

VAS Score and SR were used to assess painDCNa dose reduction for clinical efficacy against NSAID

Significant decrease in VAS pain score from Week 0 (80.38 ± 6.4) to Week 24 (67.30 ± 5.3) (P < 0.05)Significant daily reduction in DCNa from week 4 (115.04 ± 24.56) to week 24 (98.83 ± 22.32) (P < 0.05)Increase “Better” SR from week 4 (15.38%) to week 24 (61.53%)

(Cortese et al., 2015): EnvIMS case-control study

953 MS patients with disease duration of 10 years1717 controls persons

Self-reported CLO supplementation from childhood to adulthoodCLO dose: ts/month (Vit D IU/day)1-15 (≤ 200)16-30 (201-400)31-45 (401-600)46-60 (601-800)

Incidence risk of MS

CLO supplementation between 13-18 years reduces risk of adult onset MS, this makes CLO a viable source of Vitamin D.Low Vitamin D levels during

≥60 (> 800) adolescence increases risk of adult onset MS

Comments: HADS = Hospital Anxiety and Depression Scale, VAS = Visual Analogue Scale, SR = Subjective Response, DCNa = Diclofenac Sodium, 25(OH)D = 25-hydroxy vitamin D, BMI = body mass index. MS = multiple sclerosis

In summary, while the Omega-3 fatty acid composition, levels of vitamins A and D have been isolated as the main active constituents that are responsible for CLO benefits, supplementing with CLO, and not the isolated nutrients, produced positive impacts in the areas of cognition improvements, decrease in depression, decrease in pain associated with RA and decrease in NSAID requirements in RA patients. Further, the use of CLO in adolescents has been demonstrated to be effective in decreasing the risk of adult onset MS. Cod liver oil may prove to be a highly effective addition to a supplement regime with the intention of preventing and managing these chronic conditions. Moreover, these studies highlight the complementary relationship and potential synergy between vitamins A, D and omega-3 fatty acids.

Cod Liver Oil - Back to the Future

Cod liver oil is one of the oldest and most interesting medical nutrition products ever to be embraced by conventional physicians. Medicine’s formal relationship began in the 17th century with the use of Atlantic Ocean and North Sea cod and continues into the 21st century. Contemporary studies affirm CLO’s traditional application as nutritional support for immune, lung, musculoskeletal, mood, cognitive and skin health concerns.

Unlike fish and krill oil supplements, cod liver oil supplies significant levels of vitamins A and D, omega-3 fatty acid including EPA and DHA and, depending the how the cod livers are processed, an array of additional bio-actives. Clinical trials strongly suggest the potential benefits of consuming the three major components simultaneously which positions cod liver oil as unique among marine oils.

Over hundreds of years, the Atlantic Ocean and neighboring seas have become increasingly contaminated with heavy metals and environmental pollutants requiring that cod liver oil be highly refined in order to make it safe for human consumption. Currently, a much cleaner source of cod harvested from Alaska waters is available. Alaska cod livers require minimal processing making it possible to preserve the liver’s biochemically complex matrix of ratio-specific molecules. Advances in analytic techniques will assist in identifying and exploring new, naturally occurring components and the synergy between these components leading to fuller understanding of this remarkable, therapeutic marine oil.

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