Micronutrients from the Earth

The very best source of vitamins and minerals is the food you eat. However, because the animal-based typical American diet contains inadequate amounts of fruits, vegetables, seeds, nuts, legumes, and whole grains, I've been recommending that people make a conscious effort to improve their diets. In an ideal world, we would all be eating a healthy, balanced diet that includes an abundance of fresh, organic produce from our own garden and greenhouse on a year-round basis. Along with a healthy diet, a few supplements such as vitamin B12 and D3 might be all that some people need to significantly lower their risk of illness.

Before taking any supplements, be sure to check with your healthcare provider, especially if you are pregnant, nursing, taking prescription medications, have a chronic medical condition, or are planning a medical procedure. Adverse interactions and allergic reactions can occur. Make sure that any supplements you take are certified as to their purity and potency by an independent laboratory. The USP Verified Mark on a dietary supplement label indicates that the product contains the ingredients listed on the label, in the declared potency and amounts.

Just because a fruit or vegetable is labeled as "USDA-Certified Organic" doesn't mean that it is chock-full of vitamins and minerals. Produce for the mass market, even if organic, is often grown in nutrient-depleted soils, and may no longer be very fresh by the time it reaches the grocery store. Frozen and canned fruits and vegetables may actually be nutritionally superior. If you are not growing your own or shopping at farmers' markets, supplementing your diet with a few micronutrients could be good nutrition insurance. But what vitamin and mineral supplements might you actually need?.

Most of the following information on minerals and vitamins comes from the Oregon State University Linus Pauling Institute's Micronutrient Information Center. It is recommended that one becomes familiar with these micronutrients and their dietary sources to insure consumption of adequate quantities. The information below relates to the vitamins and minerals that are relevant for most people.

Dietary Supplements

For the latest research-based information and nutrition recommendations, I trust the National Institutes of Health Office of Dietary Supplements, and agree with their conclusion that micronutrients are best obtained from a balanced diet. Supplements, while not recommended as a preventive measure, may be advantageous in specific situations where a dietary deficiency, pregnancy, advanced age, or a chronic disease creates the need for an increased intake of specific vitamins or minerals.

The NIH Dietary Guidelines suggest that nutrients should come primarily from whole foods that are freshly harvested and nutrient-dense. They will contain the broadest array of essential vitamins, co-factors, and minerals, many of which are not even available as supplements. Whole foods also provide large amounts of dietary fiber that has positive health effects upon the gut microbiome.

There is a caveat about too much of a good thing not being good for you. Some nutritional supplements are potentially harmful, or even toxic, when taken in high enough doses. There is increasing evidence that excessive amounts of certain supplements, such as vitamin E, vitamin A, and beta-carotene, can be harmful. Researchers have concluded that the use of vitamin and mineral supplements as a preventive measure cannot be recommended for healthy, well-nourished people.

Consequently, the information presented below is not a recommendation for any specific supplements. There are no clear health benefits in taking multi-vitamin/multi-mineral supplements or nutriceuticals. Advice regarding nutritional supplements should never be obtained from anyone who sells them. This conflict of interest warning rules out many naturopaths, chiropractors, acupuncturists, doctors of oriental medicine, nutritionists, herbalists, and even some "holistic" medical doctors, whose sales of supplements and herbs contribute to their income. I encourage you to assume responsibility for your health care, learn as much as you can (and keep learning), use ethical professionals as your consultants, and make your own well-informed decisions.

Minerals

Sodium is an essential mineral that exemplifies the saying that too much of a good thing is not good. Decades of research have established a causal connection between sodium (salt) intake and elevated blood pressure. High sodium diets increase the risk of kidney stones. Because salt finds its way into almost all packaged foods, and is typically added to foods served by restaurants to enhance flavor, having a salt shaker on the dining table invites trouble. Read the package labels, and choose low-sodium alternatives. Be aware that table salt is typically iodized and thus provides a source of iodine in the diet. When you eliminate added salt, you may need to find other dietary sources of iodine.

Iodine is required for the synthesis of thyroid hormones. Most of the earth's iodine is found in oceans. Cruciferous vegetables such as cabbage, broccoli, cauliflower, and Brussels sprouts interfere with iodine utilization by the thyroid gland. Radioactive iodine released into the environment by nuclear reactor accidents, such as the one in Japan, will be taken up by the thyroid gland and increase the risk of thyroid cancer if there is insufficient iodine in the diet. In women, fibrocystic breast disorder has been linked to iodine deficiency. The best source of iodine is seaweed, and kelp powder can be sprinkled on salads if fresh or dried seaweed is not available.

Iron, an essential component of many tissue proteins and enzymes, is found in highest concentration in the hemoglobin of red blood cells, liver, muscles and the central nervous system. Inadequate iron reserves in the body lead to this most common of all nutritional deficiencies. Strict vegetarians, people with malabsorptive syndromes, and menstruating or pregnant women are at greatest risk for an iron deficiency, but any type of blood loss will quickly deplete the body's iron stores. Systemic iron deficiency occurs long before the onset of anemia, because the body will break down muscle in order to obtain the iron it needs for red blood cell production.

Pre-anemic iron deficiency can result in fatigue, cold-intolerance and impaired physical and mental performance. It has also been associated with restless legs syndrome. Regardless of gender, one's serum ferritin level, an indicator of the body's iron reserves, should fall within the range of 50-150 ng/ml, despite what some anemia-based laboratory norms might suggest. However, because too much iron can be harmful, supplementation with ferrous gluconate (taken with vitamin C and food) is only recommended if there is a demonstrated iron deficiency, and its underlying cause has been determined. It may be worthwhile determining one's serum ferritin level at yearly intervals to assist in the early detection of occult gastrointestinal diseases, including cancer.

Zinc is an important component of many enzymes, and is involved in the immune response and functioning of the nervous system. Phytic acids, which are present in legumes, beans and grains, are potent inhibitors of zinc and non-heme iron absorption and can result in deficiencies. Zinc intake should not exceed 15 mg/day, which is more than the Recommended Dietary Allowance (RDA). Long-term consumption of large amounts of zinc can result in a copper deficiency.

Selenium deficiency can result in an impaired immune system, and selenium supplementation has been shown to stimulate the immune response in non-deficient individuals. It may also reduce the risk for some cancers, such as prostate cancer. Selenium intake of 200 mcg/day has been prescribed for at-risk individuals, although this exceeds the Recommended Dietary Allowance (RDA). Selenium can be toxic at higher doses.

Chromium intake of 200 mcg/day has been recommended in the past. However, this exceeds the Adequate Intake level (AI), and very high doses of chromium may be harmful.

Magnesium is plentiful in plant-based foods, so eating a varied diet that includes green leafy vegetables, whole grains, oat bran and nuts daily should provide most of an individual's magnesium requirement. The RDA of magnesium for women over age 30 is 320 mg/day, and 420 mg/day for men. Avoid consuming more than the RDA of magnesium without a medical consultation.

People with diabetes, those with hypertension, and the elderly, are often deficient in magnesium. A typical multivitamin/multimineral supplement might provide 100 mg of magnesium, and additional magnesium may be necessary if the diet is deficient. Magnesium is often found in combination with a calcium supplement. Some of the favorable effect of magnesium on insulin sensitivity may be due in part to its role in calcium metabolism.

Calcium levels in the body decline through urinary excretion as dietary protein intake increases. High sodium intake also results in increased loss of calcium in the urine. Phosphates from soft drinks and food additives cause increased calcium loss in the feces. Calcium carbonate is generally the most economical calcium supplement. Most calcium supplements should be taken with meals, although calcium citrate and calcium malate may be taken on an empty stomach. To maximize absorption, take no more than 500 mg of elemental calcium at any one time. The recommended calcium intake for men and women over 50 is 1,200 mg/day. Look for calcium supplements that are labeled "lead-free" and avoid exceeding the recommended total daily intake.

While dairy products provide the majority of dietary calcium in the typical American diet, Campbell and others have mounted persuasive arguments against dairy consumption. Plants in the kale family (broccoli, bok choy, cabbage, mustard, and turnip greens) contain large amounts of calcium that is readily bioavailable. Oxalic acid, found in spinach and rhubarb, inhibits calcium absorption, as does the phytic acid in wheat bran.

Exercise in the presence of adequate calcium and vitamin D intake will have a modest effect on slowing the rate of bone loss later in life. Several other nutrients and non-nutrients influence the retention of calcium by the body and may affect a person's calcium status. Genetics, hormones, and physical activity also interact to affect bone health. High impact exercise and resistance exercise (weights) are likely the most beneficial for preventing bone loss. Lower impact exercise like walking, swimming, and cycling have beneficial effects on other aspects of health, but their effects on bone loss are minimal.

Vitamins

Vitamin D is required for optimal calcium absorption, but it affects a lot more than bone metabolism. An insufficiency of this vitamin appears to play a role in the development of diabetes, cancer, and depression. It is advisable to have one's vitamin D blood level checked, and interpret it according to the recommendation below, which is higher than labs currently suggest as normal for the average person. Unfortunately, a RDA for Vitamin D of 400 IU daily is far below what's needed for maintaining optimum health. As a consequence, 60-70% of U.S. citizens are currently Vitamin D deficient. In the Northwest, almost everyone is prone to develop vitamin D insufficiency, especially during the winter months.

Physicians have begun testing their patients for vitamin D levels using the standardized 25(OH)D blood test. If the level is lower than 40 ng/mL, they usually prescribe a vitamin D3 supplement. The recommended therapeutic dosage is 2,000 IU of vitamin D3 daily. Once a 25(OH)D level of 40 ng/mL has been reached, taking 1,000 IU/day of vitamin D3 should prove adequate for maintenance during the winter months. As with other nutrients, too much of a good thing is not good, and taking too much vitamin D3 can be harmful.

Vitamin C intake of at least 400 mg daily is important, particularly for older adults. Taking more than 500 mg in a single does has no benefit. Consider taking a daily vitamin C supplement if you are not eating lots of fresh or frozen (but not canned) fruits and vegetables. Organic produce is preferable, and from a health standpoint, it is well worth the additional expense.

Vitamin E supplementation is usually unnecessary, and may be harmful. I recommend obtaining all of your vitamin E from eating a healthy diet.

Vitamin B12 malabsorption is common, especially in older adults, and has been associated with a decline in cognitive function. Because stomach acid is required for the release of vitamin B12 from proteins in food, vitamin B12 absorption is reduced when gastric acidity is decreased. B12 deficiency is also caused by an autoimmune disease that produces a type of anemia that's found in about 2 percent of people over 60 years of age.

Folic Acid supplementation has been recommended for older adults who do not adequately absorb the folate and folic acid provided by a balanced diet. A recent study showed a 44 percent reduction in suicidal events among psychiatric patients who were taking folic acid prescriptions.

Vitamin B3 (nicotinic acid or niacin) and vitamin B6 (pyridoxine) are usually consumed in sufficient quantities in a balanced diet. High doses of niacin (greater than 35 mg/day) is sometimes prescribed for elevated cholesterol. I recommend nutritional yeast, which can add a nice flavor to salads and is rich in B vitamins.

Vitamin K is critical to the calcium-binding function of specific proteins required for the activation of seven blood clotting factors and the mineralization of bones. It also appears to play a role in cellular growth regulation. Deficiency is rare, as vitamin K is found in many foods, and bacteria in the colon produce vitamin K2, its most active form. Adults taking anticoagulant drugs, and those with liver disease or fat malabsorption syndromes may have an increased risk of vitamin K deficiency. Because older adults are at risk for developing osteoporosis, a daily vitamin K2 supplement of 250 mcg, plus at least one cup of dark-green leafy vegetables, are recommended.

Other Nutrients

Carotenoids (beta carotene, lycopene and lutein), polyphenols and coenzyme Q10 are best obtained from a varied diet containing orange-colored vegetables. Current evidence suggests that taking these nutrients in the form of supplements can actually be harmful.

Flavonoids are a large family of polyphenolic compounds synthesized by plants. It is not known whether isolated flavonoid supplements or extracts confer the same benefits as flavonoid-rich foods. Good sources of polyphenols include berries, tea, beer, grapes/wine, olive oil, chocolate/cocoa, walnuts, peanuts, pomegranates, yerba mate, and fruit skins.

Coenzyme Q10 deficiency may play a role in cardiovascular diseases, neurodegenerative diseases, cancer, and diabetes, but this requires further research. It is also unclear whether tissue CoQ10 levels are increased by supplementation.

The Bottom Line

Dietary supplements clearly do not replace eating fruits and vegetables, nor do they add to their benefits. In fact, supplements may cause adverse health consequences. I encourage people to plant their own, or participate in community vegetable gardens, and to buy fresh, organic produce from local growers at farmers' markets and food cooperatives. In general, try to eat lower on the food chain. For the home garden, be sure to include tomatoes. They are easy to grow, and are a great source of fiber, iron, magnesium, niacin, potassium, vitamins A, B6 and C, as well as the antioxidant lycopene. Kale, collard greens and broccoli can also be easily grown and are nutrient dense. Your daily diet should also include whole grains, whole beans, nuts and seeds. I recommend quinoa, edemame, walnuts and peanuts. Kiwi fruit and blueberries are among the most nutritious fruits. I also suggest including some seaweeds in your diet. Refer to the NIH Dietary Supplement Fact Sheets for the most up-to-date information and recommendations.