A basic guide to essential supplements
By Poliquin Editorial Staff
Have you been thinking of adding some supplements to your diet? Perhaps you’ve already benefited from taking magnesium for sleep or a multivitamin to improve your energy levels and now you want to branch out and improve other areas of health. With an overabundance of nutrients available from supplement companies around the world it may seem a bit daunting to figure out where to start. Here, I provide a quick summary of what you need to know about the most popular supplements and how they can benefit you. I provide a quick take away for each that highlights how it may help you live healthier and perform better.
Zinc is one of the most common and serious mineral deficiencies. About 98 percent of my clients are zinc deficient, meaning that unless you are already taking this nutrient, it’s highly likely you are deficient. Low zinc means you’ll have low testosterone and correspondingly decreased lean body mass. You’ll miss out on training gains from low zinc, and it also affects brain function and ability to concentrate. It’s essential in supporting over 100 enzyme and hormone functions in the body. Zinc plays a role in DNA synthesis and cell division, and is also linked to stomach problems, lack of immunity, and slower recovery from training or injury.
A daily intake of zinc is required to maintain a steady state because the body has no way of storing zinc. Take note that it is ineffective to measure zinc with a blood test because of how it is distributed throughout the body as a component of various proteins, and its role in maintaining homeostasis in the body. Food sources of zinc include meats, particularly oysters, beef, crab, pork, and lobster, as well as other protein sources such as yogurt, chick peas, almonds, and cashews. Generally, it’s necessary to supplement even if you get a diet high in red meat and seafood because one serving of these foods generally provides about a quarter of the daily zinc needs. Throw in lower nutrient status of present day foods and regular supplementation is advised.
To test for zinc deficiency, I use a zinc tally test, which involves placing a special zinc sulfate product on in your mouth and determining if you can taste it. If it is just like water, you are zinc deficient. If you taste something slightly metallic, you are still zinc deficient. If it tastes disgusting, your levels are probably adequate. Other symptoms of low zinc include an altered sense of taste leading to cravings of saltier, sweeter foods, and strangely, fingernail ridging. Take note that symptoms may be present, but because they are so diverse and associated with other health conditions it’s often hard to make the link to zinc deficiency without a test.
If you are severely zinc deficient (the tally test tastes like water), I suggest two tablets of my Zinc three times a day for eight weeks; then progressively reduce the dose over four weeks to one tablet a day. I also have a Zinc Tester if you want to do a tally test. Place 10 ml of zinc in your mouth (a quarter of an inch on the bottom of a small paper cup is fine. Lack of taste or a delayed taste perception suggests zinc deficiency, while an immediate taste perception suggests your levels may be adequate.
Take Away: You are probably Zinc deficient. Numerous symptoms are linked to low zinc—take note that if your child appears to have ADD or ADHD, bringing their zinc levels up may solve the problem.
2) Magnesium
Magnesium deficiency is just as common as low zinc—I have yet to see a first-time client with acceptable magnesium levels. Magnesium does wonders for people who can’t sleep. In doing interviews students on the most significant thing they learned in class, magnesium for sleep is the answer I hear most often. The benefits don’t stop there. Magnesium regulates essential brain receptors, meaning it is necessary for memory and cognitive function. Low magnesium is linked to low testosterone in men and the related problems of less lean body mass, diminished protein synthesis, and less strength gains from training. Bone disorders, diabetes, and chronic inflammation can also be prevented with adequate magnesium.
Magnesium needs increase with more physical activity, athletic participation, or strength training, meaning athletes and trainees need more. Magnesium levels will be influenced by the presence of other minerals including zinc, calcium, and potassium, as well as prescription drugs. Take note that it’s necessary to have body stores of magnesium for optimal health because this will protect against disorders such as heart disease and immune dysfunction. In addition to chronic deficiency in the Western population, the need for magnesium reserves in the body is the reason most people need to supplement along with getting it in the diet. Halibut, almonds, cashews, and green vegetables contain magnesium, but one serving of these foods will only provide about 15 percent of the U.S. RDA, a recommendation that is low.
To test magnesium levels you need to get a red blood cell measurement because this will reflect how magnesium functions in the body since about 66 percent of magnesium is found in bone and 33 percent in muscle, with only 1 percent appearing in blood. It’s very common for individuals with serum magnesium lab results in the normal range to be deficient in magnesium.Your physician or an independent lab testing company can do the test. Other symptoms of low magnesium include gastrointestinal problems, fatigue, weakness, tingling, seizures, and coronary spasms. Similar to zinc, it’s almost impossible to identify low magnesium based on these symptoms because they are related to many health issues.
Take note that the bioavailability of your magnesium will greatly influence its effectiveness in the body. Bioavailability refers to the magnesium in food or supplements that is absorbed in the intestines and ultimately available for biological activity in your cells and tissues. Even the type of outside coating of the capsule or tablet can decrease the amount absorbed into cells. Research shows magnesium oxide has much lower bioavailability than magnesium chloride, lactate, aspartate, glycinate, sulphate, or other forms. The key is to avoid cheap magnesium products because they will be completely ineffective.
Take Away: Magnesium deficiency is extremely common and will affect numerous functions in the body including sleep, brain function, muscle contractions, testosterone, strength, and the absorption of other essential nutrients such as zinc. Don’t waste money—use a high quality magnesium.
3) Vitamin D
Vitamin D could easily top this list because individuals are so commonly deficient, its importance in achieving peak health, and the synergistic effect it has on other nutrients in the body. Vitamin D is naturally made in the body in response to sun exposure, meaning that deficiency is more prominent during winter months, but really, deficiency is a major health concern year round due to how this vitamin is processed and produced in the body. Vitamin D is absolutely essential for immune function, bone health, muscle function, peak athletic performance, cancer prevention, reproductive health, and there are at least 15 other health benefits to achieving optimal levels (read the Top 25 List here).
There’s a lot of controversy about the ideal vitamin D blood level as well as differing opinions regarding the minimal daily dose. The Vitamin D Council suggests a blood level of 50 ng/ml is the minimum acceptable level, while functional medicine experts advise levels up to 80 or 90 ng/ml for best results. Avoid a level over 100 ng/ml, because although toxicity is very rare, there have been select case studies in which individuals have accidentally taken extremely large amounts of vitamin D raising levels above 100 ng/ml and having health complications.
Severe symptoms of extreme deficiency include bone disorders such as rickets and osteoporosis, while a poor immune system and regular illness is a more common sign of low levels. Just like magnesium and zinc, other symptoms are hard to link to low vitamin D because they appear with many health issues, but poor health and lack of results from exercise or strength training are major indicators.
The best way to address your vitamin D status is to get it measured with a blood test. If you are deficient or low, I suggest dosing with a large amount twice a week to bring levels up (35,000-50,000 IUs twice per week) for three months, then get it tested again. Assuming your levels are in the normal range (at least 32 ng/ml) you can use a 4,000 ng/ml dose daily. Naturally, it’s a good idea to continue testing your level if you have any concern, or at least when you get a physical. Learn more about vitamin D supplementation including the issue of excessive D levels. Two tablets of Nature's Sunshine Vitamin D3 provides an ideal 100mcg (4,000 IU) dose for most individuals.
Take Away: Vitamin D is absolutely essential for health and you are probably deficient. Taking 4,000 IUs a day is a good move. For best results, get tested and dose with vitamin D accordingly. Always attend to your vitamin D levels during the winter months.
4) Omega-3 Fish Oils
Omega-3 Fish Oils round out my top four most important supplements for the general population. In fact, omega-3s could easily be number one, but because their significance is better known, especially compared to zinc and magnesium, they appear here. Health benefits from optimal omega-3 levels include decreased chronic inflammation and pain, better cardiovascular health, peak brain function, fat loss, improved insulin sensitivity, lower blood pressure, Alzheimer’s prevention, and athletic performance. Omega-3s can improve the health of every cell in the body. The key to omega-3 supplementation is to ensure you are getting enough, that you are taking omega-3s and not omega-6s, and that your overall fat intake is balanced in favor of omega-3s.
Fatty acids are not all the same. There are omega-3s and omega-6 fatty acids and they differ greatly in promoting health in the body. Omega-6-s are very abundant in the diet such that the majority of the population has an excessively skewed ratio of omega-6 to -3 fatty acids that may cause poor health.Omega-6s themselves have many health benefits and are not bad for you, but a skewed ratio is. Ideally, you will have a ratio between the two that is close to equal, although slightly more omega-6 fatty acids are probably not a big problem. The omega-6s, which I am not going to review here are, are linoleic acid (LA), gamma-linolenic acid (GLA) and arachidonic acid (AA).
The omega-3s are docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and alpha-linolenic acid (ALA)—don’t confuse this one with the omega-6s LA and GLA listed above. DHA and EPA are the two most important because it is harder to get adequate amounts in the diet. They come from fish and grass-fed or wild meats. ALA also has health benefits but not to the degree of EPA and DHA, and it’s more abundant in most diets, coming from vegetable oils including flax and canola. Conservative recommendations on EPA and DHA intake daily are 1 to 3 grams each. For cardioprotection and lowering inflammation, 1 gram daily each has proven successful, 3 grams daily each appear to be necessary to counter rheumatoid arthritis, while higher doses are best for hypertension and improving cholesterol.
I suggest an even larger dose for optimal health and fat loss—in the range of 1 to 1.5 grams per kg of body fat, meaning if you have body fat of 20 percent you want to take at least 20 grams a day. There are no negative effects to high-quality omega-3s so you can’t overdose. If you are scared off by this high dose, start with one capsule three times a day at meals.
It is possible to get your omega-3s measured with a blood test if you are concerned, but I generally don’t find it to be necessary and the tests are expensive—over $100 a test. Do an internet search for “omega-3 test” if you are interested. One of my favorite topics is the need to rebalance fat intake.
Take Away: The omega-3s DHA and EPA are absolutely essential in your diet. They will support the health of every cell in the body. They can counter chronic inflammation, support the brain, help with fat loss, and protect the heart among other things.
5) Multi Vitamins
Taking a multivitamin is an ideal way to round out a healthy diet, and certain formulas will support specific health concerns such as chronic fatigue syndrome. A multivitamin is essential for individuals with gaps in their diet such as a vegetarian or vegan who will be missing out on a number of necessary nutrients that only come from meat or in supplement form. Generally, taking a multivitamin is not a substitute for taking the other four nutrients already mentioned (zinc, magnesium, vitamin D, and omega-3s) because individuals typically need more of these four than are included in most multis, and omega-3s are almost never included in multis. But, if you’re only able to take one supplement, a multi may be a beneficial choice.
The reason that all your supplement needs can’t be taken care of by one multi is that it takes room to package nutrients in a form that can be used in the body. Putting all the nutrients you need into one package would result in a capsule too large to swallow. For example, magnesium oxide is a cheap, small molecule that is easily packed into a capsule and it easily passes through the body without being absorbed in comparison to other forms of magnesium that are larger and more absorbable. This is why magnesium oxide or other small molecule nutrients are so common in many cheaper supplements.
You want to choose a multivitamin that fits your needs and is high quality. A quality product means that the nutrients in the vitamin will have proven bioavailability, that the product be encased in a coating that will break down rapidly in the body because this will facilitate greater absorption, but that the capsules or tablets won’t break open in the bottle before being ingested. Also, ensure that the raw materials in your vitamin has been tested for contaminants and heavy metals—these are not things you want in your vitamin supplement.
If you question the benefits of taking a multivitamin or have heard about the recent media storm regarding the flawed Iowa Women’s Health Study that linked supplement use with a slightly increased mortality rate, read my analysis of the study for more information.
A daily intake of zinc is required to maintain a steady state because the body has no way of storing zinc. Take note that it is ineffective to measure zinc with a blood test because of how it is distributed throughout the body as a component of various proteins, and its role in maintaining homeostasis in the body. Food sources of zinc include meats, particularly oysters, beef, crab, pork, and lobster, as well as other protein sources such as yogurt, chick peas, almonds, and cashews. Generally, it’s necessary to supplement even if you get a diet high in red meat and seafood because one serving of these foods generally provides about a quarter of the daily zinc needs. Throw in lower nutrient status of present day foods and regular supplementation is advised.
To test for zinc deficiency, I use a zinc tally test, which involves placing a special zinc sulfate product on in your mouth and determining if you can taste it. If it is just like water, you are zinc deficient. If you taste something slightly metallic, you are still zinc deficient. If it tastes disgusting, your levels are probably adequate. Other symptoms of low zinc include an altered sense of taste leading to cravings of saltier, sweeter foods, and strangely, fingernail ridging. Take note that symptoms may be present, but because they are so diverse and associated with other health conditions it’s often hard to make the link to zinc deficiency without a test.
If you are severely zinc deficient (the tally test tastes like water), I suggest two tablets of my Zinc three times a day for eight weeks; then progressively reduce the dose over four weeks to one tablet a day. I also have a Zinc Tester if you want to do a tally test. Place 10 ml of zinc in your mouth (a quarter of an inch on the bottom of a small paper cup is fine. Lack of taste or a delayed taste perception suggests zinc deficiency, while an immediate taste perception suggests your levels may be adequate.
Take Away: You are probably Zinc deficient. Numerous symptoms are linked to low zinc—take note that if your child appears to have ADD or ADHD, bringing their zinc levels up may solve the problem.
2) Magnesium
Magnesium needs increase with more physical activity, athletic participation, or strength training, meaning athletes and trainees need more. Magnesium levels will be influenced by the presence of other minerals including zinc, calcium, and potassium, as well as prescription drugs. Take note that it’s necessary to have body stores of magnesium for optimal health because this will protect against disorders such as heart disease and immune dysfunction. In addition to chronic deficiency in the Western population, the need for magnesium reserves in the body is the reason most people need to supplement along with getting it in the diet. Halibut, almonds, cashews, and green vegetables contain magnesium, but one serving of these foods will only provide about 15 percent of the U.S. RDA, a recommendation that is low.
To test magnesium levels you need to get a red blood cell measurement because this will reflect how magnesium functions in the body since about 66 percent of magnesium is found in bone and 33 percent in muscle, with only 1 percent appearing in blood. It’s very common for individuals with serum magnesium lab results in the normal range to be deficient in magnesium.Your physician or an independent lab testing company can do the test. Other symptoms of low magnesium include gastrointestinal problems, fatigue, weakness, tingling, seizures, and coronary spasms. Similar to zinc, it’s almost impossible to identify low magnesium based on these symptoms because they are related to many health issues.
Take note that the bioavailability of your magnesium will greatly influence its effectiveness in the body. Bioavailability refers to the magnesium in food or supplements that is absorbed in the intestines and ultimately available for biological activity in your cells and tissues. Even the type of outside coating of the capsule or tablet can decrease the amount absorbed into cells. Research shows magnesium oxide has much lower bioavailability than magnesium chloride, lactate, aspartate, glycinate, sulphate, or other forms. The key is to avoid cheap magnesium products because they will be completely ineffective.
Take Away: Magnesium deficiency is extremely common and will affect numerous functions in the body including sleep, brain function, muscle contractions, testosterone, strength, and the absorption of other essential nutrients such as zinc. Don’t waste money—use a high quality magnesium.
3) Vitamin D
Vitamin D could easily top this list because individuals are so commonly deficient, its importance in achieving peak health, and the synergistic effect it has on other nutrients in the body. Vitamin D is naturally made in the body in response to sun exposure, meaning that deficiency is more prominent during winter months, but really, deficiency is a major health concern year round due to how this vitamin is processed and produced in the body. Vitamin D is absolutely essential for immune function, bone health, muscle function, peak athletic performance, cancer prevention, reproductive health, and there are at least 15 other health benefits to achieving optimal levels (read the Top 25 List here).
There’s a lot of controversy about the ideal vitamin D blood level as well as differing opinions regarding the minimal daily dose. The Vitamin D Council suggests a blood level of 50 ng/ml is the minimum acceptable level, while functional medicine experts advise levels up to 80 or 90 ng/ml for best results. Avoid a level over 100 ng/ml, because although toxicity is very rare, there have been select case studies in which individuals have accidentally taken extremely large amounts of vitamin D raising levels above 100 ng/ml and having health complications.
Severe symptoms of extreme deficiency include bone disorders such as rickets and osteoporosis, while a poor immune system and regular illness is a more common sign of low levels. Just like magnesium and zinc, other symptoms are hard to link to low vitamin D because they appear with many health issues, but poor health and lack of results from exercise or strength training are major indicators.
The best way to address your vitamin D status is to get it measured with a blood test. If you are deficient or low, I suggest dosing with a large amount twice a week to bring levels up (35,000-50,000 IUs twice per week) for three months, then get it tested again. Assuming your levels are in the normal range (at least 32 ng/ml) you can use a 4,000 ng/ml dose daily. Naturally, it’s a good idea to continue testing your level if you have any concern, or at least when you get a physical. Learn more about vitamin D supplementation including the issue of excessive D levels. Two tablets of Nature's Sunshine Vitamin D3 provides an ideal 100mcg (4,000 IU) dose for most individuals.
Take Away: Vitamin D is absolutely essential for health and you are probably deficient. Taking 4,000 IUs a day is a good move. For best results, get tested and dose with vitamin D accordingly. Always attend to your vitamin D levels during the winter months.
4) Omega-3 Fish Oils
Omega-3 Fish Oils round out my top four most important supplements for the general population. In fact, omega-3s could easily be number one, but because their significance is better known, especially compared to zinc and magnesium, they appear here. Health benefits from optimal omega-3 levels include decreased chronic inflammation and pain, better cardiovascular health, peak brain function, fat loss, improved insulin sensitivity, lower blood pressure, Alzheimer’s prevention, and athletic performance. Omega-3s can improve the health of every cell in the body. The key to omega-3 supplementation is to ensure you are getting enough, that you are taking omega-3s and not omega-6s, and that your overall fat intake is balanced in favor of omega-3s.
Fatty acids are not all the same. There are omega-3s and omega-6 fatty acids and they differ greatly in promoting health in the body. Omega-6-s are very abundant in the diet such that the majority of the population has an excessively skewed ratio of omega-6 to -3 fatty acids that may cause poor health.Omega-6s themselves have many health benefits and are not bad for you, but a skewed ratio is. Ideally, you will have a ratio between the two that is close to equal, although slightly more omega-6 fatty acids are probably not a big problem. The omega-6s, which I am not going to review here are, are linoleic acid (LA), gamma-linolenic acid (GLA) and arachidonic acid (AA).
The omega-3s are docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and alpha-linolenic acid (ALA)—don’t confuse this one with the omega-6s LA and GLA listed above. DHA and EPA are the two most important because it is harder to get adequate amounts in the diet. They come from fish and grass-fed or wild meats. ALA also has health benefits but not to the degree of EPA and DHA, and it’s more abundant in most diets, coming from vegetable oils including flax and canola. Conservative recommendations on EPA and DHA intake daily are 1 to 3 grams each. For cardioprotection and lowering inflammation, 1 gram daily each has proven successful, 3 grams daily each appear to be necessary to counter rheumatoid arthritis, while higher doses are best for hypertension and improving cholesterol.
I suggest an even larger dose for optimal health and fat loss—in the range of 1 to 1.5 grams per kg of body fat, meaning if you have body fat of 20 percent you want to take at least 20 grams a day. There are no negative effects to high-quality omega-3s so you can’t overdose. If you are scared off by this high dose, start with one capsule three times a day at meals.
It is possible to get your omega-3s measured with a blood test if you are concerned, but I generally don’t find it to be necessary and the tests are expensive—over $100 a test. Do an internet search for “omega-3 test” if you are interested. One of my favorite topics is the need to rebalance fat intake.
Take Away: The omega-3s DHA and EPA are absolutely essential in your diet. They will support the health of every cell in the body. They can counter chronic inflammation, support the brain, help with fat loss, and protect the heart among other things.
5) Multi Vitamins
Taking a multivitamin is an ideal way to round out a healthy diet, and certain formulas will support specific health concerns such as chronic fatigue syndrome. A multivitamin is essential for individuals with gaps in their diet such as a vegetarian or vegan who will be missing out on a number of necessary nutrients that only come from meat or in supplement form. Generally, taking a multivitamin is not a substitute for taking the other four nutrients already mentioned (zinc, magnesium, vitamin D, and omega-3s) because individuals typically need more of these four than are included in most multis, and omega-3s are almost never included in multis. But, if you’re only able to take one supplement, a multi may be a beneficial choice.
The reason that all your supplement needs can’t be taken care of by one multi is that it takes room to package nutrients in a form that can be used in the body. Putting all the nutrients you need into one package would result in a capsule too large to swallow. For example, magnesium oxide is a cheap, small molecule that is easily packed into a capsule and it easily passes through the body without being absorbed in comparison to other forms of magnesium that are larger and more absorbable. This is why magnesium oxide or other small molecule nutrients are so common in many cheaper supplements.
You want to choose a multivitamin that fits your needs and is high quality. A quality product means that the nutrients in the vitamin will have proven bioavailability, that the product be encased in a coating that will break down rapidly in the body because this will facilitate greater absorption, but that the capsules or tablets won’t break open in the bottle before being ingested. Also, ensure that the raw materials in your vitamin has been tested for contaminants and heavy metals—these are not things you want in your vitamin supplement.
If you question the benefits of taking a multivitamin or have heard about the recent media storm regarding the flawed Iowa Women’s Health Study that linked supplement use with a slightly increased mortality rate, read my analysis of the study for more information.
References:
Zinc
Prasad, A., et al. Zinc in Growth and Development and Spectrum of Human Zinc Deficiency. Journal of the American College of Nutrition. October 1988. 7(5). 377-384.
Zinc
Prasad, A., et al. Zinc in Growth and Development and Spectrum of Human Zinc Deficiency. Journal of the American College of Nutrition. October 1988. 7(5). 377-384.
Shafiei, N., Gaeini, A., et al. Effect of Zinc and Selenium Supplementation on Serum Testosterone and Plasma Lactate in Cyclists After an Exhaustive Exercise Bout. Biological Trace Elements Research. July 2011. Published Ahead of Print.
Grabrucker, A., Rowan, M., et al. Brain-Delivery of Zinc-Ions as Potential Treatment for Neurological Diseases: Mini Review. Drub Delivery Letters. 2011. 1(1), 13-23.
Magnesium
Fine, K., Porter, J., et al. Intestinal Absorption of Magnesium from Food and supplements. Journal of Clinical Investigations. 1991. 88, 296-402.
Firoz, M., Graber, M. Bioavailability of U.s. Commercial Magnesium Preparations. Magnesium Research. December 2001. 14(4), 257-262.
Nielsen, F., Jornson, L., Zeng, H. Magnesium Supplementation Improves Indicators of Low Magnesium Status and Inflammatory Stress in Adults Older than 51 Years with Poor Quality Sleep. Magnesium Research. 2010. 23(4), 158-168.
Omiya, K., Akashi, Y., Yoneyama, K., Osada, N., Tanabe, K., Miyake, F. Heart-Rate Response to Sympathetic Nervous Stimulation, Exercise, and Magnesium Concentration in Various Sleep conditions. International Journal of Sport Nutrition and Exercise Metabolism. 2009. 19(2), 127-135.
Vitamin D
Ozkan, S., Jindal, S., Greenseid, K. Replete vitamin D stores predict reproductive success following in vitro fertilization. Fertility and Sterility. E-Pub: July 8, 2009.
Jensen, M., Bjerrum, P., Jessen, T., Nielsen, J., Joensen, U., Olesen, I., Petersen, J. Vitamin D is positively associated with sperm motility and increases intracellular calcium in human spermatozoa. European Journal of Human Reproduction and Embryology. 2011. 26(6), 1307-1317.
Chen, G., Kim, S., King, A., Zhao, L., Simpson, R., Christensen, P. CYP24A1 Is an independent prognostic marker of survival in patients with lung adenocarcinoma. Clinical Cancer Research. 2011. 17(4), 817-26.
Holick, M.F. Vitamin D deficiency. New England Journal of Medicine. 2007. 357(3), 266-281.?Boland, R. The role of vitamin D in skeletal muscle function. Endocrine Reviews. 1986. 7(4), 434-448.
Fletcher, R., Fairfield, K. Vitamins for Chronic Disease Prevention in Adults. Journal of the American Medical Association. 2002. 287, 3127-3129.
Omega-3s
Wall, R., Ross, R., Fitzgerald, G., Stanton, C. Fatty Acids from Fish The Anti-Inflammatory Potential of Long-Chain Omega-3 fatty Acids. Nutrition Review. 2010. 68(5), 280-289.
Buseva, D. Natural Source of Omega-3-Linseed-Oil: Its Particular Qualities and Metabolic Changes in the Organism (translated from Russian). Voprosy Pitaniia. 2010. 79(1), 13-22.
Covington, M. Omega-3 Fatty Acids. American Family Physician. 2004. 70(1), 133-140.
Simopoulos, A.P. Human Requirement for N-3 Polyunsaturated Fatty Acids. Poultry Science. 2000. 79(7), 961-970.
Multivitamins
Mursu, J., Robien, K., et al. Dietary Supplements and Mortality Rate in Older Women: The Iowa Women’s Health Study. Archives of Internal Medicine. October 2011. 171(18), 1625-1633.
Li, K., Kaaks, R., et al. Vitamin/Mineral Supplementation and Cancer, Cardiovascular, and All-Cause Mortality in a German Prospective Cohort. European Journal of Nutrition. July 2001. Published Ahead of Print.
Goddard, A., James, M., et al. Guidelines for the Management of Iron Deficiency Anemia. Gut. October 2011. 60(10), 1309-1316.
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