Friday, April 27, 2012

It's Getting Louder!

Can you hear it? From barely a whisper a year ago, the voices are getting louder. With drumsticks in hand, as the data continues to accumulate, more leading scientists are beginning to beat the drums of caution against dietary supplements.

"Emerging evidence has shown that high doses of certain supplements can actually increase the risk of cancer" wrote Maria Elena Martinez, PhD, of the University of California San Diego, and co-authors in a commentary just published online in the Journal of the National Cancer Institute.

Except for their value in treating a few uncommon nutrient deficiencies, Martinez and co-authors also wrote that "Dietary supplements have minimal supporting data for health benefits in disease prevention, particularly cancer. Despite this evidence [of potential harm], marketing claims by the supplement industry continue to imply anti-cancer benefits. Insufficient government regulation of the marketing of dietary supplement products may continue to result in unsound advice to consumers. Both the scientific community and government regulators need to provide clear guidance to the public about the use of dietary supplements to lower cancer risk."

One of the most notable comments emerging from the study related to the fact that even though "preclinical studies suggested that dietary antioxidants -- including beta-carotene, alpha-tocopherol, and vitamin C -- encouraged growth of normal cells and tissue and inhibited growth of abnormal tissue, clinical studies failed to support the favorable laboratory evidence." In layman's terms this means that animal studies cannot be relied upon to determine human usage."

Here are some excerpts from an article appearing in Medscape regarding some of the revealations:

"Several antioxidant trials have shown increased cancer risk with supplementation, the authors wrote. The most notable examples were two randomized trials of patients at high risk for lung cancer because of smoking or exposure to asbestos. Both trials showed an increased incidence of lung cancer in participants randomized to beta-carotene.

Laboratory and observational data had suggested a protective effect of folic acid against cancer, particularly colorectal cancer. However, a meta-analysis of randomized trials showed no effect of folic acid supplementation on development of colorectal adenomas (Int J Cancer 2011; 129: 192-203).

Two different randomized trials showed an increased risk of cancer (prostate) and precancerous lesions (colonic adenomas) in participants on long-term folic acid supplementation.

The Institute of Medicine recently updated its recommendations on vitamin D and calcium intake and found "there was not enough evidence to state that there is a causal association between low vitamin D intake and increased cancer risk."

Epidemiological studies have shown inverse associations between serum levels of 25-hydroxy (OH) vitamin D and several types of cancer. Three short-term randomized trials failed to demonstrate an effect of vitamin D supplementation on cancer incidence or mortality.

Observational studies have yielded conflicting data on the association between vitamin D concentrations and the risk of pancreatic cancer."

Time and again, a review of the evidence shows that supplements may not only lack clinical value, but may actually be harmful. The risk/benefit and the cost/benefit analyses therefore recommend against willy nilly usage.

Yet, modern day reincarnations of 19th century snake oil hucksters continue to thrive. Just yesterday, Dr. Oz on an episode of his show recommended no less than eight different supplements, all for weight loss or bloating. Suffice it to say, after researching each and every one, I could find no valid and reliable scientific support based on proper and sufficient studies to support seven out of eight the products, and only found mild support for one of them. I wish I had a drumstick. I know where I would want to bang it.

Yesterday morning, I did get to do a little noise-making of my own on a local Fox 29 morning news segment. The theme of the segment was how to best live to 100 and I was asked to discuss the value of natural foods over pills. With a colorful display in front of me of mostly unprocessed foods that included wild salmon, a variety of fruits and vegetables, and unsweetened almond milk, I described the benefits of each food over popular used supplements.  

There is no question that certain supplements, used selectively, may have benefit. Accordingly, we need to continue studying them to determine which fall into the usefulness category. In the interim, for the umpteenth time, don't use dietary supplements without the advice of a doctor and don't take advice from doctors who sell supplements.

At the same time, you may want to cover your ears because I suspect the noise is going to get much louder.

1 comment:

  1. New Diet Taps into Innovative Concept to Help Dieters Get Rid Of 12-23 Pounds within Just 21 Days!