Wednesday, February 26, 2014

Of Supplements, Vitamins, Placebos, and Kale

The 32 billion dollar vitamin and supplement industry has been booming during the last decade.  Financial prospects continue to look bright, as manufacturers bank on the axiom that “prevention is the best medicine”.  However, recently published scientific research has not been as kind to the industry as profits were.

Herbal Supplements
Herbal supplements are usually some form of isolated plant extract in a pill.  But an October 2013 study published by the journal BioMed Central Medicine revealed that what is inside the pill is not always the same as what is written on the outside label.

The method of analysis used for this study is known as DNA barcoding, which involves sequencing a certain fraction of a genome from an unknown biological sample that is unique for every organism.  Like a UPC symbol on a given product, a species can be identified by this small segment of its genome once the DNA sequence is determined.

In the 2013 study, 44 different samples of herbal supplements were tested, from 12 different manufacturers.  Only 48% of the supplements tested were proven to contain the herb that was listed on the label.  Obviously, a consumer would expect their odds of getting what they pay for to be better than the average coin toss. 

Furthermore, the analysis identified plant species that were not listed on the product label in 59% of the supplements.  Finding unlisted filler or contamination in a product is sloppy at best, and harmful at worst – and the latter was more than just hypothetical in several cases. 

Of the 12 manufacturers included in the study, only 2 were found to be innocent of mislabeling any of their products.  These study results were noted in the New York Times, among other mainstream news outlets.

Vitamin Supplements
From Fred Flinstone to Centrum Silver, we are told that we need to take our daily vitamins.  But the December 17 2013 issue of the highly regarded journal, Annals of Internal Medicine was not compliant.  Three separate publications in this issue challenged the expectations of the 10 million strong that have now grown, and continue to take their vitamins.

The first article was a summarization of the results from several studies released between 2005 and 2013 that examined the health effects of vitamin supplements on older individuals with normal diets.  With regards to cancer, cardiovascular disease, and mortality, no significant benefit could be observed among those who took vitamin supplements.  The total sample size of participants numbered tens of thousands of people in the sum of all the studies. 

The second study included a group of 5,947 men over the age of 65, and was aimed at determining if multivitamins boost cognitive abilities.  In standard form, the group was split, half were given a multivitamin, and the other half was given a placebo in a double-blind fashion.   No significant difference was noted between the two groups over the 12 year period of the study. 

The third study examined 1,708 individuals over the age of 50 who had previously suffered a heart attack.  Again the group was divided into one half that received placebos, and one half that received a multivitamin; administered in the standard double-blind format.  No significant reduction in cardiovascular dysfunction could be observed in the multivitamin group compared to the placebo group over the remaining life years of the participants.  This conclusion supported the findings of several earlier studies that were reviewed in the same journal earlier in the year. 

A panel of doctors and scientists including the editorial staff of the journal made special note of these three studies in an accompanying editorial.  In summary, they stated:

“Although available evidence does not rule out small benefits or harms or large benefits or harms in a small subgroup of the population, we believe that the case is closed— supplementing the diet of well-nourished adults with (most) mineral or vitamin supplements has no clear benefit and might even be harmful. These vitamins should not be used for chronic disease prevention. Enough is enough.”

The U.S. Department of Agriculture has previously made a similar assertion.  In the USDA’s 2010 Dietary Guidelines Advisory Committee Report, the following conclusion was stated:

“A daily multivitamin/mineral supplement does not offer health benefits to healthy Americans. Individual mineral/vitamin supplements can benefit some population groups with known deficiencies, such as calcium and vitamin D supplements to reduce risk of osteoporosis or iron supplements among those with deficient iron intakes. However, in some settings, mineral/vitamin supplements have been associated with harmful effects and should be pursued cautiously.” (A5 – A6)

And most recently the U.S. Preventive Services Task Force (USPSTF) published their two cents:

“The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of the use of single- or paired-nutrient supplements (except β-carotene and vitamin E) for the prevention of cardiovascular disease or cancer.  The USPSTF recommends against the use of β-carotene or vitamin E supplements for the prevention of cardiovascular disease or cancer.”

(β-carotene is metabolized in the body to form Vitamin A.)

This February 25, 2014 USPSTF report also pointed out that their recommendations are supported by independent studies conducted by the National Institutes of Health, The Academy of Nutrition and Dietetics, The American Cancer Society, and the The American Heart Association.

In spite of these studies, some people of course do remain unconvinced.  In fact, if the great biochemist Linus Pauling were alive today, it is probable that he would be numbered among them.

The Placebo
Although supplements that have been substituted with filler are nothing more than placebos at best, it is possible that those who take them can still see a benefit.  This is important to the manufacturers, because product sales are very dependent on testimonials.

In reality, the ‘placebo effect’ is not entirely an imaginary thing.  Psychology is often a component of, or at least an influence in physiology.  For instance, one study published in the journal Science showed decreased brain activity in regions of the brain where pain is registered when placebos were administered to treat a controlled pain stimulus.  Follow up studies revealed a physiological explanation: opioid production. 

In other words, the brain can be persuaded make its own feel-good medicine with the right stimulus.  The results were surprising, even to those conducting the studies.  The caveat is that such placebo effects cannot be sustained over a long period of time.

Hence, the inclusion of placebos in clinical trials – the kind that pharmaceuticals must undergo before being approved by the Food and Drug Administration.  FDA approval ensures that products are not only effective, but also safe to a determined limit and properly labeled.  Incidentally, because pharmaceuticals have been scientifically proven to induce a physiological response beyond the placebo effect, they also require a prescription.

According to the Dietary Supplement Health and Education Act of 1994, products advertised as supplements do not require this FDA approval in order to be marketed.  And so although nutritional supplement manufacturers will be held accountable if product quality is lacking in integrity, there is no mechanism of regulation to stop them from manufacturing and marketing a compromised product until and unless they get caught.  And in the meantime, they are at liberty to make unsubstantiated claims regarding the effectiveness of their products as long as they add the following asterisk:

 “*This statement has not been evaluated by FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.” 

Nature’s Vitamins and Supplements
Becoming reliant on taking pills to supplement nutrients that you assume are missing from your diet is perhaps indicative of a deeper concern: your diet.  And whether you realize it or not, some of your diet is probably already “fortified” with vitamins and minerals if you are eating processed foods (note the side of a box of Lucky Charms, for instance).

Perhaps it would be prudent to skip the supplements and go straight to the foods that will give you those important nutrients, along with natural combinations of fiber, protein, fats, and starches in proportions that the human body has been accustomed to digesting for thousands of years. 

Since you won’t see advertisements on TV or in magazines for carrots and spinach with superlative claims, here is a table of real data instead.  The data is taken from the USDA National Nutrient Database, where you can find similar numbers for over 8000 other food items.

The table here shows how much of each nutrient you will find in a 100 gram sample of the following common produce items:

Although some items may be more or less likely to be consumed in 100 gram quantities, this is the arbitrary value I chose for the sake of comparison because it is a realistic serving size for most items.  A small banana, for instance, is about 100 grams.  Among other things, you’ll note that Kale really is highly nutritious – even if some people think that it is trendy and tastes like bug spray.

On the top is shown the U.S. Recommended Dietary Allowances for men and women of a variety of nutrients – an estimation of the average daily amount required to maintain health.  It will be obvious that man should not live on bananas alone, or any other food item.  Variety is important here.  And plant life alone may not sufficiently provide what can be more easily obtained from meats, such as iron and vitamin B12.

It is worth noting that there are also maximum recommended amounts for some nutrients.  Consider that your body can quickly expel excess amounts of water-soluble vitamins when you pee, but the fat-soluble vitamins are stored away in tissue for future use.  And so consuming an unnatural amount of the fat-soluble vitamins (A, D, E, and K) can lead to a toxic buildup because your body has no quick way to clear them out.

Until the nutritional supplement industry is held to a higher standard, the consumer is left with the responsibility to follow current research from legitimate sources if they want quality assurance with their product purchases.  And although there is a mix of evidence beyond the realm of pseudoscience that shows the benefits of certain nutritional supplements, the consumer is also left with the responsibility to sort this out on their own. 

Alternatively, if you are an otherwise healthy adult and choose to follow Michael Pollan’s mantra ‘Eat Food. Not too much. Mostly plants.’, and go for a jog occasionally, then the only thing you probably need to swallow is a chill pill.