Dietary Supplements for Weight Loss: What the Science Says

Losing weight after 50 presents some particular challenges. A number of weight-loss pills are available at your local drugstore, supermarket or health food store. Even more options are available online and at fitness clubs.

Most dietary supplements marketed for weight loss have not been proven effective and some have been proven to be dangerous, especially those taking medications for serious health conditions such as diabetes and high blood pressure. Evidence has demonstrated that there is no magic pill for weight-loss. Always consult your doctor before adding a supplement to your diet.

Acai

Acai berry products have become popular in the United States, where they have been marketed as folk or traditional remedies for weight-loss and anti-aging purposes, but there is no definitive scientific evidence to support these claims.

• There is no definitive scientific evidence based on studies in humans to support the use of acai berry for any health-related purpose.
• Researches found there were no body weight changes in rats given the acai-fortified juice compared with controls.
• There is little reliable information about the safety of acai as a supplement. It is widely consumed as an edible fruit or as a juice. However, people who are allergic to acai or to plants in the Arecaceae(palm) family should not consume acai.

Bitter Orange

Bitter orange has been used in traditional Chinese medicine and by indigenous people of the Amazon rainforest for nausea, indigestion, and constipation. Current folk or traditional uses of bitter orange are for heartburn, loss of appetite, nasal congestion, and weight loss. It is also applied to the skin for fungal infections such as ringworm and athlete's foot.

• Many herbal weight-loss products now use concentrated extracts of bitter orange peel in place of ephedra. There is insufficient evidence to support the use of bitter orange for any health purpose.
• Because bitter orange contains synephrine, which is similar to the main chemical in ephedra that may speed up the heart rate and raise blood pressure. iIt may not be safe to use as a dietary supplement. There have been reports of fainting, heart attack, and stroke in healthy people after taking bitter orange supplements alone or combined with caffeine. People should avoid taking bitter orange supplements if they have a heart condition or high blood pressure, or if they are taking medications (such as MAO inhibitors), caffeine, or other herbs/supplements that speed up the heart rate.
• The U.S. Food and Drug Administration in 2004 because it raises blood pressure and is linked to heart attacks and strokes; it is unclear whether bitter orange has similar effects. There is currently little evidence that bitter orange is safer to use than ephedra.
• Bitter orange oil used on the skin may increase the risk of sunburn, particularly in light-skinned people.

Ephedra

Ephedra’s principal active ingredient, ephedrine, is a compound that can powerfully stimulate the nervous system and heart. It was used as an ingredient in dietary supplements for weight loss, increased energy, and enhanced athletic performance.

• According to the U.S. Food and Drug Administration (FDA), there is little evidence of ephedra’s effectiveness, except for short-term weight loss. However, the ban does not apply to traditional Chinese herbal remedies or to products like herbal teas regulated as conventional foods.

Ephedra Side Effects
Between 1995 and 1997, the FDA received more than 900 reports of possible ephedra toxicity. Serious adverse events such as stroke, heart attack, and sudden death were reported in 37 cases.
Ephedra may cause seizures, anxiety, difficulty urinating, dry mouth, headache, heart damage, high blood pressure, irregular heart rhythms, irritation of the stomach, kidney stones, nausea, psychosis, restlessness, sleep problems, and tremors.

Green Tea

Green tea and green tea extracts, such as its component EGCG, have traditionally been used to prevent and treat a variety of cancers, including breast, stomach, and skin cancers, and for mental alertness, weight loss, lowering cholesterol levels, and protecting skin from sun damage.

• A 2012 Cochrane review of 18 studies found that weight loss in overweight or obese adults who had taken a green tea preparation was very small, statistically not significant, and not likely to be clinically important.
• Green tea is safe for most adults when used in moderate amounts.
• There have been some case reports of liver problems in people taking concentrated green tea extracts. The problems do not seem to be connected with green tea infusions or beverages.
• Green tea contains caffeine. Caffeine can cause insomnia, anxiety, irritability, upset stomach, nausea, diarrhea, or frequent urination in some people.
• Green tea extract contains small amounts of vitamin K, which can make anticoagulant drugs, such as warfarin, less effective.

Source: National Center for Complementary and Alternative Medicine