Tag Archives: vitamin

Antioxidants: Free radical scavengers

Q: What’s an “antioxidant”?

A: Antioxidants are compounds that offset damage to the body’s cells. Antioxidants, including certain vitamins, minerals and phytochemicals, defend against injuries caused by free radicals. But what’s a free radical? Simply, free radicals are oxygen molecules floating around in your system that contain an unpaired electric charge. This single “electron” looks for a buddy to gain stability and so it destructively steals a second electron from substances like cell membranes and DNA.  Free radicals form naturally during the metabolism of food, but are also caused by cigarette smoke, air pollution and UV sun rays. While there are some benefits to free radicals, these highly reactive, unstable molecules are implicated in aging, neurodegenerative diseases and cancer. Fortunately, antioxidants can destroy free radicals, limit their formation and stimulate repair activity at the site of damage.

Antioxidant Food sources Recommended Daily Amount
Vitamin C Orange, grapefruit, mango, strawberries, broccoli 90 mg for men75 mg for women
Vitamin E Wheat germ oil, sunflower seeds, peanut butter 15 mg
Beta-carotene (Vitamin A  precursor) Carrots, sweet potatoes, broccoli None established
Selenium Brazil nuts, tuna, turkey, rice 55 µg
Lycopene Tomatoes, ketchup, watermelon None established
Lutein Dark, leafy greens (e.g. spinach) None established
Resveratrol Red grapes None established
Anthocyanin Blueberries, raspberries, plums, red grapes None established

There is no set daily recommendation for most antioxidants; however, eating more fruits and vegetables is the best way to boost your intake. Rely on whole foods, not supplements, since popping high dose capsules can have negative health effects. For example, beta-carotene supplements are associated with higher rates of lung cancer in men; however, smokers are recommended to increase vitamin C intake, due to smoke-induced oxidative damage. My take? Get your antioxidants from food sources, steer clear of mega-dose pills and stick to recommended daily amounts of vitamins & minerals.

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Filed under Fruits and Vegetables, Heart Healthy Choices, Medical Conditions, Supplements, Vitamins & Minerals

How many supplements do you take?

Q: I take a lot of vitamin and herbal supplements? Is that safe?

A: The sale of nutrient supplements is a billion dollar a year business. But whether you’re looking to ward off cancer, lose weight or make up for poor eating habits, you must be careful when taking supplements! In 1994, the U.S. Food & Drug Administration revised government regulation of dietary supplements, which include vitamins, minerals, amino acids, herbs, enzymes and many other substances. The new law determined that it is up to the manufacturer of the supplement to make sure that the product is safe, the label claims are substantiated by solid evidence and that the supplement’s content matches ingredients declared on the packaging. In short, supplements do not need approval from the FDA prior to marketing, nor does the FDA analyze the composition of these products. Manufacturers are required to investigate and alert the FDA of any reports of adverse health events associated with the product.

Supplements are indicated for certain groups of people: people with diagnosed nutrient deficiencies, pregnant women, infants, those who are lactose intolerant, perpetual dieters, those addicted to drugs or alcohol, strict vegetarians, and those suffering or recovering from illness, surgery or injury. While these may be valid reasons to be taking supplements, you should always notify your doctor of any over-the-counter products you’re consuming.

Taking supplements increases your risk of toxicities. High potency single nutrient supplements can cause accidental poisoning that can result in liver damage, shock and possible death. High doses can be very dangerous and labels can sometimes lure you with misleading or unproven claims. Certain nutrients, such as the fat-soluble vitamins A, D, E and K, can build up in your system over time. In fact, intakes of vitamin A just twice the recommended amount, taken over a few years, are associated with osteoporosis, while daily supplements of beta-carotene may increase lung cancer risk in smokers.  Always adhere to government-set tolerable upper intake levels, unless your doctor suggests otherwise. (Click here for detailed information on daily recommendations and upper limits for vitamins and minerals, divided by age and gender.)

Supplements can also affect the absorption and metabolism of medicines you take and nutrients in the food you eat. For example, when taken in a pure form, zinc interferes with copper and calcium absorption and calcium hinders magnesium and iron absorption. In addition, the herbal product St. John’s Wort can severely limit the effectiveness of AIDS medications and is not recommended when simultaneously taking an antidepressant from the SSRI family. Clearly, taking multiple over-the-counter supplements increases your chance for harmful food-drug and drug-drug interactions.

My best advice is to try and get all your nutrients from food! Taking a multivitamin can help “cover your bases,” but any amount of certain vitamins or minerals consumed in excess of what your body needs will generally be excreted. While a banana and a tablet may both contain potassium, the fruit provides a balanced assortment of nutrients, fiber and phytochemicals (beneficial, active plant compounds) that can temper the effects of the mineral.

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Filed under Supplements, Vitamins & Minerals

Whole vs. Refined Grains

Q: Why are whole grains healthier than refined grains?

A: The wheat kernel contains four main components: the germ – rich in oils, vitamins and minerals, the starchy endosperm, the nutrient- and fiber- packed bran coating and the inedible husk. A “whole grain” refers to a grain milled in its entirety, except for the husk. Examples of nutritious whole grains include amaranth, barley, buckwheat, bulgar, corn, millet, quinoa, brown rice, oats and whole wheat. Refining grains removes the coarse parts of the kernel, which leaves only the starchy endosperm and causes the loss of fiber, vitamins and minerals.  All refined products (e.g. white bread, white pasta) are required to be enriched with iron, thiamin, riboflavin, niacin and folate to combat deficiencies in these nutrients. Unfortunately, even enriched products remain nutritionally inferior to whole grains. For example, a slice of enriched white bread contains only 18% of the amount of vitamin B-6 that a slice of whole grain bread contains, and only a quarter of the amount magnesium and fiber.

The bottom line? Whole grains are much more nutrient dense than refined grains. When at the grocery store, do not judge by color alone! Look for products, such as breads, pastas, cereals and crackers, which contain “100% whole grains” or the word “whole” in front of the grain name on the ingredient list. For example, the ingredient label on a box of Cheerios tells us that the product is made from “whole grain oats.” Be cautious – “wheat bread” or “multi-grain crackers” may list  “unbleached enriched wheat flour” first on the ingredient list, which means it’s not made with healthy whole grains!

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Filed under Grains