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FAT-SOLUBLE VITAMINS: LIPIDS AS A BIOLOGICAL SOLVENTEMILY TRUSSLER INTRODUCTION TO ORGANIC CHEMISTRY SIMMONS COLLEGE SUMMER 2015
Definition of a a Vitamin
Presentation Pathway
Vitamins A, E, K Sources Applicability
Vitamin D as a case study for fat-soluble vitamin relevance
Chemical Concepts
What is a vitamin?A vitamin is an organic molecule - mostly it functions either to assist enzymes or to preserve chemical structures in the body
like all organic compounds, they are either water-soluble or lipid-soluble
Chemical Concepts
Lipids
Solubility
Polarity
Artificial lipids
Quick Lipid ReviewLipids are non-polar molecules, and act as solvents to other non-polar molecules
Lipophilic, as we know from lab, means that a solute or compounds is soluble in lipid solvents.
Triglyceride/triacylglycerols lipids are made through the esterification of glycerol and 3 fatty acids (glycerol = molecule made up of three alcohol groups; fatty acids = carboxylic acid chains, each with long carbon R chains attached)
Other lipids, such as cholesterol, are variations on that formula
Vitamin Solubility and PolarityFat-SolubleWater-Soluble
Polar vitamin molecules
Carried in bloodstream
Daily intake/replenishment required
B- and C vitamins
Non-polar vitamin molecules
Dissolve in lipids
Stored in lipid adipose deposits in body
Do not require daily intake
A, D, E, K
Note how each molecule only has, at maximum, 1 polar group in a predominantly non-polar molecule. That's why these are lipophilic!
Why (real) Fat is Fat-tasticLipophilic vitamins last longer, because unlike water-soluble vitamins, they do not wash through the body; instead, we keep a supply in our fat cells
Vitamins A, D, E, and K serve some of the most exciting and important functions in our bodies
Some of our favorite food combos support a healthy body! - Sweet potato with butter - Sautéed kale in olive oil - Broccoli with cheddar cheese - Guacamole
Fat Fails
There are downsides to being fat-soluble
With a supply in fat storage, overuse of supplements can lead to vitamin toxicity, (hypervitaminosis) which can cause extreme symptoms
Artificial fats, such as Olestra, also dissolve vitamins; the downside there is that these undigestible fats go through the body, taking the vitamins from your lunch with them
These vitamins require dietary fat to dissolve and be taken into fat storage. Dieters who avoid fat with their sweet potatoes, kale, and other lipophilic-vitamin foods will likely not extract all the "superfood" goodness!
Choosing the best fat for the job....
Among the real fats available in our diet, we can choose saturated fats or unsaturated fats
As solvents, neither is better than the other. Vitamins will dissolve readily in meat fat or vegetable oil
The choice depends upon overall diet, as excessive saturated fats can obviously lead to health problems
Also, many fat-soluble vitamins come in a healthy-fat package, such as fish and eggs.
Fat-Soluble Vitamins: A, E, K, D
Retinol"A" Good Start
- True vitamin A is found in animal products, but dietitians prefer beta-carotene sources - Eating fruits/vegetables rich in beta-
carotene, which converts to vitamin A when needed in the body, prevents toxic levels
- hypervitaminosis A can lead to orange skin, bone softening in children, hair and skin dryness and liver damage.
-For eye and bone health
- Scientists realized the vision connection during WWI, because the vitamin A-deficient soldiers had poor vision at nightfall.
The "E"xcellent Vitamin: Tocopherol
Vitamin E is known for its benefits to skin, but it is truly the great protector
As an antioxidant, vitamin E prevents damage to red blood cells, as well as to vitamins A and C
Works best in combination with the nutrients found in real, natural food - pill supplements have proved ineffective at providing all of vitamin E's natural benefits
Vitamin E comes from nuts, seeds, vegetable and soy oils and some fortified products, like cereals. Deficiencies are rare, but affect the brain and blood.
"K"ale's Got ItVitamin K is the blood clotting vitamin - but it also helps with protein production that keeps blood, bones and kidneys functioning normally
Leafy greens are the best sources, as well as cruciform veggies
Deficiency in vitamin K obviously causes hemorrhaging, and so intake is vital for children and patients taking Warfarin/blood thinners. Babies are given vitamin K injections for a week after birth.
K1 and K2 K1 is the green leafy vitamin we know, while K2 is found in fermented foods like cheese. Both help with clotting, but K2 is easier to absorb than K1.
"D"octor's Orders: D as a Case Study
Now that we've addressed the other fat-soluble vitamins, we can use the last one to investigate this topic
Vitamin D is an excellent case study for fat-soluble vitamins and why they are SO important in the body
VITAMIN D: CASE STUDY
The Sunshine Vitamin? Not Exclusively
Vitamin D in the D3 (cholecalciferol) form comes from the conversion of a form of cholesterol on the skin (7-dehydrocholesterol), but it can also be found in fish and egg yolks
The same UV rays can produce D2 in yeast and some fungi - this is the only pill supplement suitable for vegetarians, as D3 is usually derived from fish livers
D2 is the only prescribed form of D supplementation
Exciting new research has discovered that other tissues in the body produce the active form of vitamin D (- working with other biomolecules, it can actually shrink tumors in those tissues (brain, breast, colon, etc.)
It Does WHAT??Vitamin D is an amazing molecule that has exciting biological abilities
Vitamin D stimulates the production of a peptide that can actually kill tuberculosis in the blood
In conjunction with other biomolecules, vitamin D can shrink tumor growth
Acts as a cytokine (basically a messenger to the immune system)
Vitamin D has "apoptotic" and anti-angiogenetic properties - meaning that it can kill cancer cells and prevent the re-growing (http://www.ncbi.nlm.nih.gov/pubmed/23094926)
D Mechanisms7-dehydrocholesterol converts to D3 under UV light.
This travels to the liver, where D3-25-hydrolase converts it into Calcidol (25-OH D3), a prohormone
This Calcidiol then travels through the kidneys, where another enzyme converts it to the active form, 25-(OH)2 D3, Calcitriol.
A supplement pill form goes directly to liver
D2 (Ergocalciferol) is hydroxylated by different enzymes, creating 24-OH- D2 and 25-OH- D2, that are used the same way as the D3 molecules in the body (maybe)
D InhibitorsThe reason why many people need the FOOD sources of vitamin D is that our ability to synthesize our own D is highly dependent upon:
Dark skin
Poor diet
Obesity
Breast milk nursing vs formula
Home location
Age
Deficiency TiesAs more and more research is performed and published, low levels of vitamin D are turning up as partners to some major health problems:
Osteomalacia, osteopeonia, osteperosis, fractures
Diabetes
Heart disease
Asthma and allergies
Immune disfunction and immunomodulatory issues
Cancers - especially breast and pancreatic
Depression and mood disorders, including schizophrenia
All vitamin deficiencies are serious. Deficiency is rare with all other fat-soluble vitamins, which is why hypovitaminosis D is now being so thoroughly researched
Pediatric ApplicationsFinland has produced many medical studies about vitamin D supplementation early in life. In one study, over 5,000 babies were given 2000 IU daily for their first year, and compared to a control group. Over 10,000 babies altogether were followed until age 32.
The supplemented babies had an 80% decreased chance of type 1 diabetes, compared to national statistics
The control group had a 200% increased chance of the same disease, compared to national statistics
Because of the length of pediatric studies, we are only finding out about results now, so pediatric recommendations will take time to change.
Other Special Considerations
Breast milk has pretty much no vitamin D, but as the Finland study found, it is incredibly important for babies and young children (it also has minimal vitamin K, see that slide for details)
Deficiencies in children generally lead to rickets (bending, bowing bones) - this is why our milk has been D-fortified since the 1930s.
D in the Diet: It Comes Pre-Packaged!
It's easy to remember which foods contain D because most of them come pre-packaged with their own solvent: fat!
Salmon and fatty fish, like mackerel
Eggs
Fortified dairy, including milk, cheese and yogurt, butter
The low/non-fat versions include fortified cereal and orange juice, and mushrooms, and some soy products
Remember, vitamins A, E, and K are found in many of these same foods, or tastes best with them!
SO EAT YOUR VITAMINS....WITH FAT!!
Bibliographyhttp://articles.mercola.com/sites/articles/archive/2015/01/11/vitamin-k1-k2.aspx
https://www.vitamindcouncil.org/blog/the-anti-cancer-actions-of-vitamin-d/#
http://www.chemistryexplained.com/Pr-Ro/Retinol.html
http://www.accessexcellence.org/AE/AEC/CC/vision_background.php
http://www.nlm.nih.gov/medlineplus/ency/article/000350.htm
http://www.chemistryexplained.com/Di-Fa/Fats-and-Fatty-Acids.html
http://www.chemistry.wustl.edu/~edudev/LabTutorials/Vitamins/vitamins.html
http://www.ext.colostate.edu/pubs/foodnut/09315.html
http://m.ajcn.nutrition.org/content/87/4/1080S.full
https://www.grc.com/health/pdf/vitamin_d_deficiency_medical_progress.pdf
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3012634/
Images and graphs from the websites above, sciencemom.com and Google Image searcb engine
https://m.youtube.com/watch?v=R3jV4I-Er2w (USMLE Fat-Soluble Vitamin Tutorial)
http://lsresearch.thomsonreuters.com/maps/924/
http://healthyeating.sfgate.com/saturated-vs-unsaturated-fats-lipids-8611.html
wikipedia (general information)
http://www.chemistryexplained.com/Pr-Ro/Retinol.html
