In this lecture we're going to look at the micro nutrients that are the minerals. Minerals along with vitamins remember they don't provide any energy but they are very important in the sense that they help our body unlock the energy from the other macro nutrients that we have in our diet. Micronutrients are needed in smaller amounts, so like the vitamins, minerals you will find listed on nutrition facts panels or the labels of your foods in micrograms or in milligrams, and that's also the amount needed by the body, to be listed in micrograms or milligrams as well. Where as the vitamins were classified based on their solubitlity, fat and water soluble, the classification of minerals is a little bit different. The classification for minerals can be defined as either major minerals or trace minerals. Now trace minerals doesn't mean that they're any less important than the major minerals. It's just that the major minerals are those that are needed in amounts of more than 100 milligrams per day from your diet. And they're present in the body in amounts of greater than, 1/10 of a percent of your body weight. So the major minerals are things like sodium, potassium. Chloride calcium phosphorus, magnesium and sulfur. Your trace mineral are no less important but just needed in smaller amount by your body. Less than 100 mg per day. But they constitute a smaller percentage of your total body weight. So these are things like iron, copper, zinc, selenium, iodine, chromium. Fluoride, manganese, molybdenum, and there's a couple of other ones as well. A little bit about minerals as a group. Minerals are elements, so you'll sometimes hear those terms used, interchangeably. And they're elements that are needed by your body, in very small amounts, in order to help your body be as optimally healthy as possible. And also to help maintain some of the different bodily functions. Minerals are available naturally in

unprocessed foods. They're in some processed foods, but in general, the vitamin and mineral content of processed foods, tends to be lower than those of unprocessed foods. Unless the manufacturers have added back in some vitamins or minerals. In order to maintain optimal health, minerals should be consumed in the correct proportions. Minerals can be toxic if they're taken at very high levels, so for a number of the minerals for which there is sufficient data, scientists and researchers have set forth what are called safe upper intake levels. Another thing that some minerals do is they work together as what are called co-factors and other minerals serve as electrolytes. The minerals that act as electrolytes include sodium, potassium and chloride and the very important role of the electrolytes are to control your body's nerve impulses and the conduction of those nerve impulses. Electrolytes also help your body to maintain its appropriate pH balance and to prevent the unhealthy conditions of acidosis and alkalosis. There are a couple of things in your diet that might actually decrease or inhibit your body's ability to absorb. Different minerals from the foods that you eat. So some example of these are things like oxalates. Oxalates are found in greens like spinach, kale, chard, and turnip. And even though those foods are certainly healthy for you, and those foods do contain a little bit of calcium and iron Compounds like oxalates and phytates in those same foods actually prohibit to some degree the absorption of those minerals, calcium and iron, as well as other minerals. What I'm not saying is that you shouldn't be eating those foods. But just be aware that you're not going to absorb 100% of the iron and calcium that you find in foods like dark green leafy vegetables. Tannins are compounds that we find in certain types of tea and in some grains. And they can inhibit or decrease iron absorption. And lastly, Phytic acid. What are called phytates are found in foods like soy, bran and whole grains and

they can interfere with the proper or optimal absorption of calcium, zinc, iron and magnesium. Phytic acid is broken down by yeast, so the bioavailability of the minerals tends to be higher in yeast leavened foods, such as bread. The bottom line here is that you're not always going to a store 100% of the vitamins or minerals from foods that you eat. But if you eat a variety of food, some might contain oxalates, some might contain phytates. Some might not have any of these inhibitors. The goal is that you will hopefully achieve or obtain and absorb the appropriate amount of minerals and vitamins that you need. Now, we're going to focus on the mineral, calcium. 99% of the calcium in your body is found in the solid mineral deposits that exists in your bones and your teeth. The other one percent is found circulating in intracellular fluid, blood and extracellular fluid. Calcium is important because it helps you, your body transmit nerves. It helps your muscles contract appropriately. It also helps to regulate your blood pressure and to release hormones. For individuals that have a deficiency of calcium, this negatively impacts their bone health. They'll have low bone mineral density, and be at risk for the conditions osteopenia and osteoporosis. Osteopenia refers to weakened bones; osteoporosis refers to porous bones. Individuals who have low bone mineral density, osteopenia or osteoporosis are at very high risk for developing fractures. There's also the possibility that you might have excessive amounts of calcium. And the upper limit for calcium for, in the United States from the Institute of Medicine is set at 2.5 grams, or 2500 milligrams. To put that in perspective, a cup of milk has about 300 milligrams, so this is upwards of eight cups of milk. Most people don't get excessive amounts of any vitamins or minerals from foods however. They tend to do it from supplements. So, if you take very high dose calcium

supplements, it can cause things like gas, bloating, or constipation. High intake can also increase your risk of kidney stones, can cause urinary and blood calcium levels to rise which in turn can cause headaches. Kidney failure can lead to tissue calcification and then it offsets or reduces your bodies ability to absorb other minerals. So the point here is that for most people they should get the majority of the calcium from foods in their diet. But we know that there are individuals who can't meet their calcium needs. From foods alone. They might need supplements, but they should be careful not to go over this 2,500 mg per day level. Which most calcium supplement are about 500 mg per supplement. So you'd have to be taking 5 or more pills per day. It's not likely, but just be aware, as is the case with all supplements, too much of a good thing is not a good thing. How much calcium do individuals need? In the United States, the RDA is 1,000 milligrams per day. So the upper limit was 2,500 milligrams per day. 1,000 milligrams a day works out to roughly the equivalent of three cups of milk a day. As you get older, if you're older than age 51. Your needs actually go up to 1200 milligrams a day and then in the US on an average women don't get enough calcium but men do okay so men get on average a 1000 milligram, women get 800. Now, there's a whole group of people for whom they can't tolerate dairy foods because of the conditional lactose and they might get a little bit calcium fro different plant foods or perhaps soy foods. But they would then need to fill in the gap in order to get to that 1,000 milligrams by taking supplements. It's true that the best sources of dietary calcium are the dairy foods, yogurt, milk and cheese. There is to a lesser degree, however, some calcium in non-dairy foods, like dark green leafy vegetables, almonds, legumes, sardines, canned salmon with bones, and fortified juices. The bones part from the salmon is because you're eating the bones of another

animal; you're eating their calcium deposits, as well. Calcium supplements are very important for individuals who for whatever reason don't get close to 1000 mg of calcium a day from the diet. Those might include people who are lactose intolerant, they lack the enzyme, lactase, that would allow them to efficiently break down the milk sugar, lactose. If you're allergic to milk, if you're a vegetarian who doesn't eat milk products, if you're a vegan who doesn't eat animal, any animal products. Or if for any other reason you have a very low calcium diet, a supplement might help you out. A couple tips about supplements for calcium. You want to keep it to 500 milligrams or less per supplement, because your body really doesn't have the ability to absorb more than that at one time. Some people might need to take, two 500 milligram supplements, at different times in the day. You want to avoid products that contain aluminum, or magnesium. because these actually, increase your calcium losses. If your taking the supplement called calcium carbonate, you might want to know that it is roughly 40%, calcium. And you need to take those supplements with food. If you're taking calcium citrate, there's a lesser percentage of the supplements that's calcium, just 21%. But it doesn't require that you take it with food. Why are we so concerned about calcium? Well, we know that adequate calcium status plays some sort of role on our bone health. And the jury is certainly still out as to what degree that is. There's some very interesting population studies done around the world looking at people who consume very low levels of calcium and yet have very low levels of risk, of hip fracture. Hip fracture is usually a good indicator that that person has some sort of low bone marrow or density. In different parts of the world, people have different levels of vitamin D exposure. If they spend more time outside. They might be engaged in more physical

activity. There's all sorts of things besides just calcium intake which can impact your bone health. We know that peak bone mass is achieved in most people somewhere around age 30. After age 30, the process of bone resorption occurs at a rate that's faster than bone synthesis. So, basically once you get 30 or some where around there, your body is breaking down bone more quickly than it's building up. This leads to reduction in bone mass and we'll call it bone mineral density. Prolonged loss of bone mineral density Will lead to the condition of osteoporosis. Osteoporosis ends up giving you bones that are porous and should you fall or bump into something or hurt yourself, you're at increased risk for having a fracture because of the very fragile nature of those porous bones. In this slide, you're seeing the comparison between a nice. Healthy, normal bone and an osteoporotic bone. Notice that in the healthy bone, the latticework is really nice and tight. That's a strong bone, where if that person fell or bumped into something, it's not likely that that would cause a fracture. In this individual, you can see that the prolonged low bone mineral density has led to a degradation of that latticework, and there's big porous spots in there. Where if that person fell or came into contact, or bumped into something to hard, they would very likely have an increased risk for a fracture. Who's at risk for developing osteoporosis? How do you get those porous bones that you saw in the previous slide? Gender certainly plays a role. We know that fractures and osteoporosis are two times more common in women than they are in man. Men tend to be larger and heavier. And in the case of osteoporosis, being heavier is actually protective. The older you get, bone loss is a natural part of aging. And older people tend to be at higher risk. Those who are of African descent have more dense bones that do Caucasians or individuals from Southeast Asian

populations. So in this case, being of African descent would actually be protective. Your family history plays a role. If you have someone in your family who has osteoporosis, you yourself are at increased risk for developing the condition as well. Your body size, if you're thin and light and frail, higher risk of having osteoporotic bones. Tobacco weakens your bone mineral density, so smoking is not a good idea if you're trying to reduce your risk. Long term alcohol abuse can reduce bone formation and long term alcohol abuse also interferes with your body's ability to effectively absorb calcium. And not to mention that people who are drinking a lot of alcohol tend not to be drinking a lot of milk. Diet also plays a role. Diets that are low in calcium and vitamin D play a role in the development of osteoporosis. If you have very low calcium intake during those important bone-forming years of teenage-hood and adolescence, you're going to have lower bone mineral density. And, you actually have a quicker rate of bone loss as an adult if you have a low calcium diet. What we're basically saying is, that if you're already an adult and you didn't eat a ton of calcium growing, you don't have to worry that much. If you don't have establish osteoporosis, you can actually slow the rate at which your body loses bone, by increasing the amount of calcium. Vitamin D and by doing what's called weight bearing exercise. And weight bearing exercise is rally any exercise that excludes biking and excludes swimming. In those exercises your own bones aren't bearing the weight of your own body. So calcium, vitamin D and weight bearing exercise can help slow the rate at which you lose bone in adulthood. If you're interested in learning more about calcium or any of the other minerals, you should check out some of these websites from Harvard Heath, the Food and Agriculture Organization, and the United States Institutes of Health.