Few topics in medicine are more controversial than the use of dietary supplements.
The results from large-scale clinical trials often remain inconclusive. These trials are usually designed on the basis of positive findings from epidemiological studies and laboratory evidence. A common view is that the negative findings from the clinical trials present a well established evidence that the specific supplement is irrelevant to disease and that the epidemiological studies are biased.
An alternative explanation is that some trials are designed to test the effectiveness of supplementation without screening for the participants’ baseline levels of the nutrient. In other words, it’s possible that some people don’t respond because they consume sufficient amounts of the nutrient in question. In fact, some nutrients lack proper thresholds, i.e. the researchers don’t know how much the body actually needs.
At present, it seems that food is the best source of the variety of nutrients our body needs. Current guidelines recommend at least five portions of fruit and vegetables each day. Unfortunately, our busy lifestyles often make it hard to follow these guidelines. So, if you have decided to supplement, there are some important tips to keep in mind.
First and foremost, do not over do it. It’s a known paradox that dietary supplements enthusiasts are usually people who need supplements the least. This is because they often eat balanced diets and make healthy lifestyle choices. If you do use supplements, avoid taking more than the recommended dose of any nutrient through supplements unless specifically recommended by your doctor.
It is especially important to avoid taking too much of the vitamins and minerals such as Vitamin A, Calcium (for men), and Iron.
Vitamin A is a fat-soluble vitamin essential for vision, skin health, and bone growth. Fat-soluble vitamins are stored in fat tissues and liver, and are released to bloodstream as needed. Because these vitamins are stored for long periods, toxic levels can build up and quietum plus potentially cause toxicity. To be on the safer side, look for supplements containing Vitamin A in the form of beta carotene rather than retinol or retinyl versions. Beta carotene is stored in fat tissue and converted to Vitamin A as the body physiologically demands it, therefore avoiding toxic levels. Also, try not to take more than the Recommended Dietary Allowance.
There is good evidence that high intake of calcium increases the risk of prostate cancer and may also increase heart attacks. A large epidemiologic study found that intake of more than 1,500 mg of calcium per day might increase the risk of aggressive and fatal prostate cancer. So men should avoid taking calcium supplements. (Harvard Health Publications; “Minerals and Vitamins”).
Large doses of iron supplements can cause an iron overload, which can damage body tissues and increase the risk of infection, heart disease, liver cancer, and arthritis.
Moreover, taking high doses of vitamin C increases the body’s’ ability to absorb more iron, potentially causing iron overload.
Always store an iron containing supplement away from children to prevent acute poisoning that might be fatal.
General rules of thumb
Choose products that are verified by ConsumerLab.com or bear the U.S. Pharmacopeia Dietary Supplement Verification Program (USP-DSVP) mark. These supplements would in fact contain the ingredients listed on the label and their actual strength. These products would dissolve within 30 to 45 minutes after ingestion so that the nutrients can reach the bloodstream, and not pass through the body intact. The verified supplements do not contain harmful levels of contaminants such as heavy metals (e.g. lead and mercury), bacteria, molds, toxins, or other contaminants. At certain levels these contaminants can pose serious risks to one’s health.