Supplements: Benefit of the doubt or doubts about their benefits?

Supplements have been in the news lately.  Last October, FDA acting director general Dr. Kenneth Hartigan-Go issued an advisory to the public to be wary of several food supplements which are being marketed on TV as having therapeutic effects.  He stressed that these supplements were approved as food products and not as drugs or medicine.  As such, they are not intended to treat or cure diseases.

That same month, the Philippine Society of Medical Oncology and the Philippine College of Physicians, in a press conference with the theme “Dietary Supplements: Investigating the Claims,” warned that there is an increasing number of herbal supplements being promoted in the Philippines through media as both food and medicine, although they have no approval for their therapeutic claims and they lack scientific proof for their supposed beneficial effects.

The use of some supplements also became controversial when research studies done last year raised alarm on their possible serious side effects.  For example, US scientists said last July that they have confirmed a surprising 2011 study that found a higher risk of prostate cancer among men who consume omega-3 fatty acids, raising new questions about the safety of supplements.  The study, done at the prestigious Fred Hutchinson Cancer Research Center in Seattle and published in the Journal of the National Cancer Institute, reported a 71-percent higher risk for dangerous high-grade prostate cancer among men who ate fatty fish or took fish oil supplements, which are often touted for their anti-inflammatory properties.

A more recent analysis showed that there is little evidence that vitamin and mineral supplements protect people from cancer and heart problems.  Based on these findings, a US government-backed panel issued draft recommendations that echo its previous conclusion: It cannot recommend for or against taking vitamins and minerals to prevent those conditions. 

“At this point in time, the science is not sufficient for us to estimate how much benefit or harm there is from taking vitamin or multivitamin supplements to prevent cancer or heart disease,” Dr. Michael LeFevre said.  He is co-vice chair of the US Preventive Services Task Force (USPSTF), which issues recommendations to help guide doctors and health systems.  The USPSTF sponsored the new analysis.

The panel’s draft statement also says neither beta-carotene nor vitamin E should be taken to prevent heart disease or cancer.  Previously, beta-carotene was found to further increase the risk of lung cancer among people who are already at an increased risk.  Furthermore, the panel concluded that there is no consistent evidence that supplements — multivitamins or otherwise — affect the risk of heart disease, cancer or death among adults.

WHAT DO WE DO NOW?

So, what do we do now?  That’s a good question.  Here’s where we stand today — but keep an open mind as recommendations may change as more strict scientific results become available.  Let’s look at the more popular supplements used by people today, either to preserve health or ward off illness, or to attempt to treat specific conditions or diseases.

• Calcium.  In theory, we should be able to get enough calcium from food.  However, many of us don’t consume enough dairy products and other calcium-rich foods.  If your diet falls short, supplements make sense; calcium carbonate and calcium citrate are best.  Many doctors recommend calcium supplements for women who have a high risk for osteoporosis.  Men should limit their intake to recommended values (see Table) as some evidence suggests very high levels may increase the risk of prostate cancer.  And a 2011 report linked calcium supplements to an increased risk of heart disease.  It’s not a proven risk, but it underlines the need for a careful study of the risks and benefits of supplements.

• Vitamin D.  A long time ago, most people got their vitamin D by working in the field.  But as work shifted from the farm to the office and as we’ve learned to use sunscreens to reduce the risk of skin cancer and wrinkles, many Filipinos now lack sufficient amounts of the “sunshine vitamin.”  Vitamin D is needed to absorb calcium from the intestines; that’s why vitamin D is important for healthy bones.  It’s hard to get this vitamin from your diet so supplements do make good sense for most adults.  The form known as D3 is usually recommended but D2 is also effective.  If you want to be sure you need this supplement, ask for a blood test; levels of at least 30 nanograms per milliliter are considered best.

• Antioxidants.  Vitamin E, vitamin A, beta-carotene, and vitamin C were the favorite vitamins in the 1980s and 1990s.  But subsequent research failed to show any benefit against heart disease, cancer, or other illness.  In fact, the opposite was noted.  For example, moderately high doses of vitamin A increased the risk of fractures, and high levels of vitamin A have been linked to an increased risk of prostate cancer; beta-carotene increases the risk of lung cancer in smokers; and vitamin E increases the risk of prostate cancer and has been linked to an increase in respiratory infections, heart failure, and overall death rate. 

Bottom line: Do not take antioxidant supplements.  One exception: People with moderate or advanced age-related macular degeneration (AMD) may benefit from special antioxidant supplements that also contain zinc.

• Vitamin B complex.  The three most commonly used B vitamins are B6 (pyridoxine), folate (also known as folic acid in its synthetic form), and B12 (cobalamin).  The B vitamin’s benefit has been due to its ability to lower homocysteine levels.  High levels of homocysteine, an amino acid, have been linked to a high risk of heart disease and folic acid, alone or with B6 and B12, has been shown to reduce homocysteine levels. Vitamin B12 is found only on animal-based foods, so strict vegetarians may need supplements.  In addition, many old people do not make enough of the stomach acid that’s needed to liberate B12 from animal products so it can be absorbed.  That is why a B12 supplement in the elderly is a reasonable option. Folate supplements during pregnancy have been shown to have reduced significantly the incidence of birth defects.

• Glucosamine and chondroitin.  A 2010 meta-analysis of 10 research studies covering 3,803 patients concluded that these supplements have no benefit.  There are doctors, however, who allow some patients with arthritis to try these supplements for a month or two to see if they provide any joint pain relief. 

• St. John’s wort.  This herb may reduce your symptoms of depression but depression can be a serious illness and care should involve preferably a psychiatrist. The supplement can interact with prescription antidepressants and other medications.  If you think you may be depressed, get professional help instead of dabbling with St. John’s wort or, for that matter, SAMe (S-Adenosylmethionine), another supplement that may help mild depression.

• Melatonin.  Small doses of this “dark hormone” may help with symptoms of jet lag or insomnia, but much more research is needed.

• Saw Palmetto.  Initial reports suggested that this supplement might reduce symptoms of benign prostatic hyperplasia (BPH) — but later research dashed those hopes.  Many other supplements are touted for the prostate, but evidence of benefit is lacking.  Fortunately, excellent prescription drugs are available for BPH.

Don’t swallow all the claims

We’ve heard a lot of encouraging news about supplements.  A series of studies hailed vitamin D as a possible defense against a long list of diseases, including cancer, diabetes, depression, and even the common cold.  Omega-3 fatty acids have been touted for warding off strokes and other cardiovascular events.  And antioxidants such as vitamins C and E and beta-carotene were seen as promising silver bullets against heart disease, cancer, and even Alzheimer’s disease.

Here’s the big caveat: Many of those exciting supplement studies were observational — they didn’t test a particular supplement against a placebo in a controlled setting.  The results of more stringent randomized controlled trials haven’t yielded the same good news. 

Here are some of the supplements that have failed closer scientific scrutiny:  zinc (for the common cold), echinacea (for respiratory infections), yohimbine (for erectile dysfunction), DHEA (for aging, memory loss, sexual potency, and everything else), ginseng and ginkgo biloba (for any purpose), and chromium (or any other supplement) for weight loss.

In September 2010, Consumer Reports published a list of “dirty dozen” supplements which it advised consumers to avoid due to harmful effects on the heart, liver, and kidneys.  These supplements include aconite, bitter orange, chaparral, colloidal silver, coltsfoot, comfrey, country mallow, germanium, greater celandine, kava, lobelia, and yohimbe.

Buyer beware!

It is often difficult to balance sober scientific judgments against forceful claims for health in a pill.  In the final analysis, the decision is yours.  But here are a few precautionary measures to observe:

• Beware of testimonials and endorsements, especially from celebrities.  Even the most well-meaning success stories can’t establish a product’s safety or efficiency.  Only good research can. 

• Beware of meaningless terms.  These include all-natural, clinically proven, antioxidant-rich, anti-aging, and other vague but seductive claims that a product will promote heart health, prostate health, sexual prowess, energy, weight loss, fat loss, muscle power, and the like.

• Beware of extravagant claims.  If it sounds too good to be true, it is usually not true.

• Beware of the idea that if a little is good, more is better.  For example, a high intake of folic acid may increase the risk of certain tumors. 

• Beware of interactions between supplements and medications.  Always tell your doctors about any supplements you take and ask specifically about interactions with your prescription and over-the-counter medications.

Remember, taking supplements can also be harmful in their own right if they keep you from taking good care of yourself or getting the medical care you need.

So, even if you take supplements, be sure to eat well, exercise regularly, and work with your doctor to keep your blood pressure, cholesterol, and blood sugar in good control.

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Some of the information in this article were sourced from www.health.harvard.edu