Do dietary supplements work?

Many diets have some type of supplemental support. The variety must be confusing for people who are dieting.

Garcinia Cambogia has been seen as a possibility to add to diets with the intention of reducing hunger- Kathryn Borg

I will take a look at some of them and try to explain how they work, and indeed, if they do work or are just another commercial addition to this huge dieting industry.

A product called Garcinia Cambogia is a recent addition to many diets I have seen and been involved with. Ironically, this is not a new product, like aloe vera; it has been around for centuries.

It comes from a tree and was used in southeast Asia to make meals feel more filling. So in the past it wasn’t exactly a dieting product. However, someone has seen it as a possibility to add to diets with the intention of reducing hunger. Ideally, it should suppress appetite and reduce the conversion of carbohydrates stored as fat.

There have been placebo-controlled trials with this supplement (known as hydroxycitric acid, or HCA) and it was found that it can reduce appetite (Int. J. Obes., 1997). Other advantages were weight loss, cutting calorie intake and increasing fat burning. Others found HCA worked well with chromium, which I will discuss later.

Alternatively, some other studies have reported that this is not the case. One trial found no evidence of weight loss (JAMA, 1998). However, it seems that how HCA is taken, which dosage and the quality of product all make a huge different in these trials. I have also experienced that some manufacturers have a better product; however, this is the case with many supplements.

Moving on to chromium. This is a mineral which is also used to support those on a diet. Chromium is a naturally occurring mineral which has a role in the action of insulin and in the metabolism of carbohydrates and fats.

It is most commonly used now as a weight loss aid. Once again it is claimed to decrease appetite; in addition it is purported to increase metabolism and therefore increase lean body mass.

Looking at the evidence to support the use of chromium, in one study 20 overweight women followed a mild diet and exercise regime supplemented with chromium, or a placebo, for two months.

They then changed over and for another two months took either the placebo or the chromium.

The results in this study showed that those who took the chromium after taking the placebo first lost significantly more fat and less muscle compared to those who took the chromium first.

This sounds very confusing; I can’t make it sound simpler and it was a rather complicated way of conducting a trial. However, it was very interesting to observe the differences in the two groups, which were dependent on when the chromium was taken. (Diabetes Obes. Metab., 1999).

It seems that the way chromium is formulated also makes a difference. It can be chromium picolinate or niacin-bound chromium. Once again, not helpful to the layman who is trying to decide which would be the best supplement to accompany a diet.

An amino acid called L-Carnitine is also a supplement that has been used to accompany a diet. It is purported to help the body turn fat into energy. It was initially used by sports people, but became a popular addition to diets.

L-Carnitine is said to aid weight loss, mainly by boosting fat metabolism. This is a product available on many websites and one of them states that it decreases fat levels in the blood and weight loss is then easier.

Interestingly, there are results not supporting weight loss. A review of weight loss supplements states ‘no trials demonstrate that L-Carnitine is effective for weight loss’ (Am. Fam. Physician, 2004).

Some studies have suggested that this supplement has the potential to stimulate fat metabolism (Nutrition, 2004). Dietary carnitine is found in red meat and dairy products.

A supplement found naturally in food such as apples is Pyruvate. This is made in our bodies as a result of glucose metabolism. It is another supplement made popular in sports nutrition.

Once again, this supplement has been adopted by the dieting industry and is purported to reduce body fat and enhance the body’s ability to use energy efficiently.

In one study the supplement proved supportive for weight loss while consuming a low-fat diet (Am. J. Clin. Nutr., 1994). Overweight adults showed a greater weight reduction when taking Pyruvate. Another study showed positive results too; however, it was in conjunction with exercise and diet over a period of time (Nutrition, 1999).

A recent review of Pyruvate was published in the Journal of Obesity (2011). The reviewers explained that only a small number of participants were used and for a short period of time; however, the conclusion was that it may be beneficial for weight loss.

It must be stressed that these supplements are not designed to be used in isolation; they must accompany a healthy diet with an exercise programme, and not all of them show positive results.

kathryn@maltanet.net