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Vitamin Overdose: Are You Getting too Much of a Good Thing?

October 11, 2011

With the crisp autumn air and brilliant shades of red and orange in the trees comes a less pleasurable side of fall: the beginning of flu season. Though there are different theories as to why we’re more vulnerable to contagious viruses in the cold weather, it can sometimes seem inevitable that we’ll catch a cough, sore throat or the sniffles come wintertime.

In an effort to stave off sickness, many people choose to take supplements of vitamins, minerals, and herbs that are known to help the body fight disease. Though supplements can be literally life saving for people with nutritional deficiencies, a new study published in the American Journal of Clinical Nutrition cautions against the overuse of dietary supplements.

According to the study, people who take multi-vitamin and multi-mineral supplements are a health-conscious crowd that tends to eat healthy, well-balanced meals. These people are getting enough nutrients from their food, and by taking additional dietary supplements, they may actually be overloading on vitamins and minerals that can cause potentially serious health problems. “We always would hope that the people who are taking dietary supplements are the ones who need it the most, but it doesn’t seem to be true,” says Cheryl Rock, a nutrition researcher at the University of California, San Diego.

On the other side, many people fear that even when eating a diet rich in whole, seasonal fruits, vegetables, and whole grains, it’s still difficult to get the proper amount of nutrients necessary to fight illness. According to recent studies, fruits and vegetables are not nearly as nutritious as they once were. Biochemist Dr. Donald Davis of the University of Texas at Austin studied 43 garden crops and found that the average vegetable today is up to 38% lower in nutrients (including riboflavin, vitamin C, calcium, iron, phosphorus, and protein) than produce from 50 years ago.

Davis attributes this decline mostly to the industrialization of agriculture: “During those 50 years, there have been intensive efforts to breed new varieties that have greater yield, or resistance to pests, or adaptability to different climates. But the dominant effort is for higher yields. Emerging evidence suggests that when you select for yield, crops grow bigger and faster, but they don’t necessarily have the ability to make or uptake nutrients at the same, faster rate.”

If you do choose to add nutritional supplements to your diet, it’s important to keep in mind that much of the concern about “vitamin overdose” risk lies in the difference between water-soluble and fat-soluble vitamins. It’s difficult to overdose on water-soluble nutrients like vitamin C and vitamin B, for example, because your body will only absorb what it needs – any excess amounts are excreted in your urine.

Fat-soluble vitamins like vitamins A, D, and E, however, are stored in your body tissue and if you consume too much, can accumulate to potentially dangerous amounts known as hypervitaminosis. The same risk of overdose goes for minerals such as iron, zinc, and selenium, so it’s important to monitor the amount you’re taking when incorporating these supplements in your diet.

In addition to nutritional supplements, there are other wonderfully simple ways to make sure you’re keeping your immune system strong as flu season approaches: get plenty of sleep, stay hydrated, and perhaps most importantly, wash your hands often!

What’s your stance on nutritional supplements?