The latest buzz on melatonin and omega-3 supplements

Melatonin and omega-3 are probably among the most commonly used supplements today. Melatonin gained popularity some years ago as a dietary supplement to prevent or treat jet lag, and omega-3 has been touted for its myriad health benefits, from atrial fibrillation to Alzheimer’s disease.

Recently, there had been many well-designed studies that looked into the different effects of these two dietary supplements. You will be surprised by the findings. Here are the latest on melatonin and omega-3.

Melatonin: Beyond Jet Lag

A popular dietary supplement, melatonin has been promoted simply as a way to treat insomnia and prevent jet lag. No more. Now, it’s touted to treat or prevent everything from fatigue, anxiety, headaches, and depression to dementia, tinnitus, irritable bowel syndrome, and skin damage from the sun. Not to mention heart disease and cancer, as well as menopausal symptoms and all the other signs of aging. There are now even melatonin-based drinks abroad that are supposed to help you relax. Anything that’s marketed as a cure-all should set off warning bells.

• The darkness hormone. Melatonin is a hormone produced by the brain’s pineal gland; it is also found in some edible plants. It has been called the “darkness hormone” (in contrast to vitamin D, the “sunshine hormone”) because it is secreted at night; exposure to light suppresses it. Since melatonin affects circadian rhythms — that is, our internal body clock and sleep/wake cycle — and promotes drowsiness, it has long been used as a sleeping aid.

Recent research on isolated cells and lab animals has shown that melatonin has antioxidant, anti-inflammatory, immunological, and potential anti-cancer effects. Such findings don’t mean, of course, that it has these same effects as well, to any significant degree, in people.

Melatonin tends to decline as people age. Some researchers have suggested that various age-related changes and conditions (such as declining immunity, cognitive losses, and sleep disturbances) are due at least in part to this drop in melatonin. Marketers often use the notion that declining melatonin levels need to be replaced as a selling point for supplements — similar to the way estrogen “replacement” therapy was once promoted as a way to prevent chronic disease and keep women feeling young. But many compounds produced by the body decline with age. And even if you replaced them, that wouldn’t necessarily help keep you healthy or prevent the effects of aging — and it wouldn’t necessarily be without risk.

• Some well-supported claims. A 2009 review by Cochrane Collaboration (which evaluates medical treatments) concluded that supplemental melatonin is effective for preventing or reducing jet lag, though not all studies have had positive results. Melatonin appears to be safe for short-term use, it said, and should be recommended to adult travelers flying across five or more time zones, particularly in an easterly direction (Manila to the US, for example).

The Natural Standard (which reviews complementary and alternative treatments) has also found “strong” evidence for its use in treating insomnia in the elderly and enhancing sleep in healthy people. But for all the other supposed benefits, it said, the evidence is conflicting or inconclusive.

• Points to keep in mind. Here are some important things to consider if and when you decide to take melatonin:

1. The long-term safety and effectiveness of melatonin supplements are unknown. Prolonged use, for instance, may undermine the body’s ability to produce the hormone naturally. Hormones are powerful substances that, even in small doses, can produce unexpected and unwanted results, as was seen with estrogen therapy. In many countries, melatonin’s availability is restricted; at least one formulation has been approved for prescription use in Europe, Australia, and Israel for up to three months of use in people over 55.

2. Various adverse effects from melatonin have been reported, including high blood sugar, breast swelling in men, decreased sperm count, gastrointestinal irritation, sleepwalking, and dizziness. Melatonin may interact with other hormones, so pregnant women, those trying to be pregnant, and children shouldn’t take it. If you have a chronic disease, such as diabetes, liver or kidney disease, clinical depression, or an immune disorder, consult your doctor before taking melatonin.

3. For some people, melatonin helps them doze off faster but doesn’t help them stay asleep.

4. Like other sleeping pills, melatonin can produce a “hangover effect” and drowsiness the next day. That’s risky if you are driving or operating machinery.

5. There’s no consensus about which dose, schedule or formulation of melatonin are best for various sleep disorders, according to a report in Sleep Medicine Reviews in 2009. It pointed out that some studies show that the effects of melatonin may not even be clearly related to dose. In any case, as with other dietary supplements, you can’t even be sure that the dose listed on the label is accurate.

6. Though melatonin is found in some edible plants, including rice, banana, cherries and grapes, – it’s unclear how much you need to consume of these foods in order to raise blood levels of melatonin. A small recent study in the Journal of Medicinal Food found that tart cherry juice, compared to placebo drink, helped older people with insomnia sleep a little better. The subjects drank 16 ounces a day (the equivalent of 100 cherries), supplying 250 calories. That’s a lot of juice and calories for a “modest” effect.

Words to the wise: Consider taking melatonin supplement only for jet lag and insomnia — and only for occasional or short-term use. If you have chronic insomnia or another sleep disorder, consult your doctor, who may refer you to a sleep specialist. Don’t take melatonin in hopes of protecting yourself from cancer or the effects of aging — or any other health matter not related to sleep.

Omega-3 Fish Oil

A flurry of new research on fish oil supplements is raising eyebrows as well as questions about just how “miraculous” those omega-3 fatty acids really are. “Live long, stay strong,” say the ads for fish oil pills, touting not only omega-3’s familiar heart-health benefits but also mental and cellular protection. But recent clinical trials have reminded nutrition scientists that, after all, the strongest data linking omega-3s and reduced cardiovascular risk come only from previous observational studies.

Indeed, new studies on fish oil (omega-3) supplements have recently made news. Most of these were large well-designed clinical trials, which are few and far between in the world of dietary supplements. The results were mostly disappointing:

• Heart disease. In a Dutch study of people who already had a heart attack, omega-3 supplements did not reduce the risk of cardiovascular events over a 40-month period. This conflicts with some prior studies that did find a protective effect, as well as the advice from the American Heart Association that heart attack patients should take omega-3s. But unlike the older research, this New England Journal of Medicine study included mainly people who were already on “state-of-the-art” medications such as statins and blood pressure drugs, which could help explain the lack of effect of the supplements.

• Atrial fibrillation. In a large study of people with this heart rhythm abnormality, high-dose omega-3 supplements did not reduce the risk of recurrence over a six-month period. It has been theorized that one way omega-3s from fish or supplements may reduce the risk of cardiovascular disease is by preventing heart rhythm problems, and some previous studies have suggested this. This study, in the Journal of the American Medical Association (JAMA), was the largest clinical trial to test this theory.

• Pregnancy. Though pregnant women are often advised to take omega-3 supplements (DHA, in particular, the main omega-3 fat in the brain) to boost their children’s mental development and prevent postpartum depression, these DHA capsules have neither effect, according to a large Australian clinical trial published in JAMA.

• Alzheimer’s disease. Omega-3 supplements do not help slow progression of the disease, according to a study (also in JAMA) of Alzheimer’s patients in Oregon, who took either DHA or a placebo for 18 months. Some previous observational studies suggested that high intakes of DHA help prevent or slow dementia, including Alzheimer’s.

• Cognitive decline. In contrast, another placebo-controlled study, in the Alzheimer’s and Dementia journal, found that DHA supplements, taken for 24 weeks helped improve memory and brain function in people over 55 with mild cognitive impairment. This suggests that to help the brain, the supplements need to be started early, before mental decline progresses too much.

So, as far as taking fish-oil supplements is concerned, the jury’s still out. The bottom line for omega-3, for now, remains much the same as for most nutrients: Eating a variety of healthy foods is better than trying to get nutrition from pills.