Micronutrients Part II: Minerals and Phytochemicals
Last month, I discussed the various vitamins -- what they do, which ones act as antioxidants, and how to make sure you get enough of each. This month the focus is on the other micronutrients -- so-called because the body needs relatively small amounts of them, but important to health nonetheless -- minerals and phytochemicals.
Minerals are divided into two classes, macrominerals and microminerals. As their names imply, macrominerals are needed in larger amounts than microminerals.
The macrominerals are calcium, phosphorus, and magnesium. They provide structure and function to the bones and teeth, and each plays a role in nerve transmission and the relaxation and contraction of muscles, including the heart.
Calcium: As you probably know, calcium is important to the formation and maintenance of strong bones and teeth throughout the life cycle. It is also involved in blood clotting. Calcium deficiency can cause osteoporosis.
Milk, cheese, and other milk products are good sources of calcium, as are tofu, canned salmon and sardines, and nuts. Milk is something that a lot of people give up when they become adults, but it is still important that they get enough calcium, either in their diet or through a supplement. You may have good bones now, but you still need enough calcium to maintain your bones and to perform calcium's other functions. If you don't take it in daily, these other life-sustaining functions will take calcium away from your bones, and this could be big trouble.
You need vitamin D in order to absorb calcium from the diet.
Phosphorus: Phosphorus participates in the energy cycle by turning the food we eat into fuel the body can use. Like calcium, phosphorus is also involved in muscle contraction and nerve transmission, and we need phosphorus to make body proteins. Phosphorus is part of your DNA, which controls heredity. As part of cell membranes, phosphorus plays a protective role by regulating what comes in and goes out.
Phosphorus deficiency can result in neuromuscular, skeletal, blood, and kidney abnormalities, and extreme deficiency can be fatal. Phosphorus deficiency is frequently seen in individuals who are on long-term total parenteral nutrition (also called "TPN") or who use phosphorus-binding antacids to excess.
There is a relationship between calcium and phosphorus. For optimal absorption of each, the relationship should be one to one. Too much phosphorus causes poor absorption of calcium. In a study that compared female athletes who drank carbonated beverages -- a rich source of phosphorus -- with those who didn't, those who drank the soda had more bone fractures. Unless you are on TPN or taking phosphorus-binding acids, the chance of a deficiency is rare. This is one mineral that you are more likely to get too much of rather than too little, especially if you take supplements or drink carbonated beverages to excess. Too much phosphorus can cause calcium deficiency, leading to osteoporosis.
Besides carbonated beverages, phosphorus is found in milk and milk products, meat, fish, nuts, and legumes.
Magnesium: Needed for energy production and protein synthesis, magnesium is found in whole grains, legumes, leafy green vegetables, nuts, and chocolate. Deficiencies can cause muscle spasms, tremor, convulsions, and mental derangement.
Stress, a common condition in people with HIV, can deplete the body's stores of magnesium. The anti-PCP drug Bactrim interferes with magnesium absorption. Diarrhea increases magnesium losses, and alcohol decreases absorption. If you think your diet and your multivitamin together don't provide the recommended 280 to 350 mg per day, you need to supplement.
Jon Kaiser, a holistic AIDS doctor from San Francisco, recommends adding magnesium to your regimen along with calcium for the management of peripheral neuropathy.
This mineral is not toxic, and unlike calcium it is not given up by the bones for all the functions it has to perform. When you are not getting it from food and supplements, you risk a deficiency state.
Iron, selenium, and zinc are needed only in very small amounts. The latter two, because of their participation in antioxidant enzyme systems, have a particular role in HIV.
Iron: Iron is essential for the formation and function of red blood cells. Vitamin C promotes the absorption of iron.
Anemia is the iron deficiency disease, but the anemia associated with HIV is not necessarily caused by inadequate iron (see "Caution," below).
Men's vitamin formulations are already omitting iron because of problems associated with men's health, including heart disease and colon cancer. Vitamin-mineral formulations made for adults over 50 years of age are low or lacking entirely in iron because of these findings. Women's formulations still have iron because of the significant monthly blood loss associated with menstruation. Women need extra iron and have an outlet for it until they pass menopause.
In the early 1940s there was a campaign to fortify food with iron to combat the high incidence of iron deficiency anemia. This did not solve the problem, and because of the new problems associated with excess iron and disease there is a move to discontinue the practice. For the time being, though, watch for iron in fortified cereals and breads. Iron is also abundant in meat, fish, and seafood. Peas and other legumes are vegetable sources of iron that is better absorbed with foods rich in vitamin C.
CAUTION: If you suspect iron deficiency, do not self-medicate with an iron supplement. Let your doctor be the judge.
An oversupply of iron in HIV is potentially harmful. Excess iron can deposit in the liver and the heart. When oversupplied, iron can stimulate free radical production and further damage the immune system. In one study, iron levels were higher in people with HIV. Remember, free radical production causes cell damage.
Selenium: Selenium deficiency is most commonly associated with a form of cardiomyopathy (heart disease) called Keshan disease. It is also associated with anemia. Mary Romeyn, an AIDS doctor in California, reports clearance of thrush on selenium supplementation. Research also points toward a protective effect against various cancers, including prostate, colon, and liver cancer.
The best sources of selenium are Brazil nuts (one nut = 100 mcg), cashews, fish, seafood, organ meats, and whole grains. The problem with whole grains is that the amount of selenium in the grain depends on the selenium in the soil where it is grown. The content in the grain is unreliable because the selenium content in the soil varies from one geographical area to another.
The toxic level of selenium is not known, but for safety's sake we recommend no more than 200 mcg per day of supplementation. Check your supplement, and if you decide to medicate with Brazil nuts, don't overdose -- no more than two a day, and enjoy the rest of your food.
Glutathione peroxidase: Most important for HIV is the selenium-containing enzyme glutathione peroxidase. This enzyme acts together with the other antioxidants discussed last month (vitamins E and C and beta carotene) to destroy free radicals before they destroy our cells. Studies in HIV-positive populations correlate deficiency with infections and fevers.
Glutathione and selenium together make up glutathione peroxidase. Glutathione is an antioxidant that seems to play a role in HIV management. It appears to be the major intracellular (T-cells, and others) antioxidant. Glutathione is a protein made in the liver by dietary amino acids (breakdown products of protein). According to a group of researchers from California, a decrease in glutathione levels accelerates the destruction of T-cells and mortality from AIDS. Glutathione also helps the liver to detoxify and protects red blood cells from damage and the eyes from cataracts.
Zinc: Because zinc is essential for the synthesis of DNA (your particular genetic material), it is essential for cell division, cell repair, and cell growth -- for every cell in your body. It is needed for growth, development, wound healing, and reproductive function. The immune system relies on zinc. Zinc is a component of over twenty enzymes. One of these enzymes, superoxide dismutates, has been shown to enhance defense systems.
Zinc deficiency can result in loss of taste and smell acuity, slow wound healing, fatigue, increased susceptibility to infection, and recurrent viral infections. Testosterone levels can also drop as a result of zinc deficiency. AZT lowers zinc levels. If you have diarrhea, you are at risk for zinc loss.
Food sources of zinc include brewer's yeast, egg yolks, fish, lamb, legumes, meat, pumpkin and sunflower seeds, and whole grains. Your multivitamin with minerals contains 15 mg. Up to 50 mg per day is safe, but more than 100 mg per day is thought to be immunosuppressive.
For years we have heard that eating fruits and vegetables is good for us. Vitamins and minerals were isolated in the early 1900s. Then fiber was found to be protective. In the past few years, we have isolated chemical compounds in fruits and vegetables and other plant foods that also play a crucial role in metabolism and seem to prevent cancer, heart disease, and other chronic illnesses. Collectively, we call them phytochemicals ("phyto" is Greek for "plants"). They are disease fighters that have no nutritional value in the traditional sense that vitamins and minerals do.
Phytochemicals work by various mechanisms: They activate enzymes that can inactivate carcinogens; they suppress the growth and division of cancer cells; and, as antioxidants, they act to disable potential cancer-causing cells. Heart health seems to respond to antioxidant action. The effects on osteoporosis, kidney disease, and other chronic diseases are under investigation.
The phytochemicals in fruits and vegetables are usually brightly colored. Good examples are the carotenoids. These are related to vitamin A and beta carotene, but have no vitamin activity. Lycopene and lutein are carotenoids. The following is only a sampling, so a good rule of thumb is to get fruits and veggies of every color every day, so you don't miss out on any of the phytonutrients and micronutrients your body needs.
Lycopene is responsible for the red color in tomatoes and other red foods, such as watermelon, pink grapefruit, and guava fruit. There are compelling studies that look at the reduction of prostate cancer in men who routinely eat cooked tomato products. Lycopene also fights off cervical and breast cancer and heart disease. Olive oil enhances the disease-fighting effects of lycopene.
Lutein is what colors spinach and other green leafy vegetables. It's also in broccoli and tomatoes. Lutein is an antioxidant that protects your eyes against cataracts and macular degeneration, a common cause of blindness.
Flavanoids are phytonutrients found in citrus fruits, grapes, berries, broccoli, apples, onions, tea, and gingko biloba. These are antioxidants that inhibit blood-clot formation (blood thinners), thereby protecting against heart disease. They are also thought to inhibit cancer enzymes that are involved in metastatic disease (cancers that travel to other parts of the body and spread the disease).
Allyl sulfides are in garlic, onions, leeks, and chives. They stimulate anticancer enzymes, detoxify carcinogens, lower cholesterol, and may enhance immunity.
Micronutrients In The Diet
Soy-based products have been a mainstay of Japanese and other Asian diets for centuries, and these cultures have a lower incidence of various cancers than we do in the West. Besides the prevalence of soy-based foods, these Eastern diets also contain lots more veggies than ours do.
Soy foods include tofu, tempeh, soy milk, and soy cheese. As textured vegetable protein, soy is used to replace meat in processed foods like frozen burgers, meatloaf, and hot dogs. Some of the phytochemicals in soybeans are also found in legumes, such as kidney beans, chickpeas, lentils, peas, and the like. Soy and legumes are great sources of protein, fiber, and other micronutrients besides phytochemicals.
Cruciferous vegetables -- cabbage, broccoli, Brussels sprouts, cauliflower, and kale -- protect against breast- and cigarette-smoke-induced cancer.
Fiber is a plant chemical that protects against gastrointestinal cancers by speeding carcinogens through the digestive tract. Fiber binds to and dilutes carcinogenic substances.
I suggest you at least take a high antioxidant multivitamin and mineral supplement. If you have neuropathy, go for the B complex and B12 supplementation. Magnesium and calcium might help too.
A supplement should never substitute for a healthy diet. Supplements don't have protein, calories, or fiber, and they don't have phytochemicals and other good things you get from food.
Good nutrition takes planning, but it doesn't have to be difficult. Think of some of your favorite foods, and go through the foods I talked about above and last month. Sugary foods are usually considered empty calories because they have very few micronutrients. But popular foods -- things like pizza, spaghetti and sauce, chili, rice and beans, and peanut butter and jelly sandwiches -- are loaded with nutrients, and they taste good too.
So, pop your multivitamin with mineral supplement in the morning with a power-packed breakfast, and have a healthy day!
Donna Tinnerello is an HIV Nutrition Specialist at Cabrini Medical Center and Bailey House, and is Chair of Nutritionists In AIDS Care (NIAC).