Besides Ephedra, there are many weight control ingredients that have been waiting in the wings. Some of these ingredients, common in dietary supplements, are becoming GRAS in functional foods. Others are food ingredients that have just become popular in the U.S. Still a few more are becoming more deeply rooted in the dietary supplement markets—and new clinical evidence backs them up. The ingredients in this article have been classified according to different areas of nutrition: the lipids, the dietary fibers, the nutrients and the botanicals.

The Lipids

 

  • CLA (Conjugated Linoleic Acid). The scientific evidence for CLA in weight loss was strong for laboratory animals (mice, pigs, rats, chicks), but controversial in humans. Recently, human clinical studies have started to change that.

    CLA is an isomer of one of the two essential fatty acids, linoleic acid (the other being linolenic acid). Linoleic acid is first in the chain of the omega-6 fatty acids, and found mostly in vegetable products. However, CLA is frequently found in meat and dairy products naturally. CLA used in supplements most likely is manufactured from safflower oil. Common claims for CLA are that it builds muscle while reducing fat, induces thermogenesis, fights cancer, and is an antioxidant. Typical dosage recommendations are between 3-5mg daily.

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  • MCT (Medium Chain Triglycerides). Ever wish you could bend the rules of metabolism after you ate a meal high in fat, and have those nutrients converted to something that wasn't going to sit on your hips? MCTs seem to hold this promise. They are exactly what they are named, fat molecules that have "medium"? chain lengths (6, 8, or 12 carbons), and behave more like carbohydrates in the body than fats. They are made quickly available as an energy source or as a source of ketone bodies. While their exact role in weight loss is not yet clear, as little clinical evidence has proven their many claimed benefits of improving endurance, promoting fat loss, increasing the metabolic rate, and maintaining muscle mass, it is true that they generally act more like carbohydrates in the body. Daily recommended use is up to about 1g/kg of bodyweight.

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  • DAG (1, 3 diacylglycerol). DAG and triacylglycerol both are components of common vegetable oils in our diet. Recent scientific research supports the hypothesis that a DAG-rich diet results in reduced fat accumulation, when compared to one rich in triacylglycerol. DAG is promoted on the market as an alternative vegetable oil that looks, tastes and has a similar nutritional profile as ordinary vegetable oil, but that is not metabolized like it.

    Due to the 1 and 3 positions on the glycerol backbone of DAG, the diglycerides are converted to monoglycerides during metabolism, and then sent to the liver for immediate breakdown. In triacylglycerol, the molecules are packaged into chylomicrons and mainly passed to the lymphatic system and bloodstream to be stored as fat. Toxicological and nutritional research also has shown no adverse effects in consuming DAG-rich oil, and no adverse toxicology.

    In one double-blind, placebo-controlled study, dietary DAG was found to reduce the accumulation of fat, especially abdomen fat, and to be a possible method of reducing disease risk associated with abdominal fat (such as cardiovascular disease). The fat accumulation in men who consumed DAG was compared with those who consumed triacylglycerols in a diet targeted at 50g per day. The authors found DAG significantly reduced the accumulation of total fat, visceral fat area and subcutaneous fat area of the abdomen, compared to triacylglyerol consumption.1
     

    The Dietary Fibers

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  • Insoluble vs. Soluble Fiber. One of the original "health ingredients,"? fiber is well accepted for its role in reducing the risk of heart disease, lowering LDL and total cholesterol, preventing constipation (insoluble fiber) and reducing the risk of colon cancer. Fiber is a broad term best distinguished by its properties as being either soluble or insoluble fiber. Soluble fiber can be broken down by bacterial enzymes and is soluble in water, whereas insoluble fiber cannot, and passes through the digestive system without being digested. Foods usually contain both types of fibers.

    Fibers have been used in some weight loss formulations in order to promote satiety after meals, and to slow blood sugar absorption in the gut (as it may act as sort of a "brush-barrier"), balancing blood sugar and insulin levels. Additionally, the newer area of fat-blocking fibers has been popularized by the pharmaceutically produced fiber, orlistat (Xenical[tm]).

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  • Chitosan and Fat-Blocking Fibers. Chitosan was one of the first fibers promoted as a dietary supplement claiming to block fat absorption. A dietary fiber that is the by-product of shellfish processing (the shell part), chitosan is a large, positively-charged fiber that can attract and bind with fatty acids (that carry a negative charge). Once bound, these complexes of chitosan and fatty acids form "films"? that may pass undigested through the digestive system, not being specifically hydrolyzed. Since chitosan also attracts and binds with cholesterol (and other neutral lipids), it also is promoted as a cholesterol-reducing agent. Clinical studies on chitosan have been mixed, with recent studies showing it has no effect on weight loss. Proponents of chitosan claim the reason these studies have failed is due to the fact that chitosan needs to be used with a calorie-restricted diet at the correct dosage.

    One earlier Italian clinical study prescribed a combination of chitosan supplements and a low-calorie diet (1,000cals/day). The results of this study were favorable, and supported the idea that chitosan should be used in combination with other dietary modifications. After 30 days of supplementation, the chitosan group produced a 16-lb. weight loss, whereas the placebo group only found a 7-lb. difference. In animal studies, chitosan has been reported to prevent an increase of body weight, hyperlipidaemia and fatty liver induced by a high-fat diet.2

    More recent studies on chitosan's effectiveness have been negative. A pilot study performed at the University of California (Davis, Calif.) concluded that chitosan supplementation (5.25g daily) during a high-fat diet did not increase fecal fat content and, therefore, did not block fat absorption.3 Another study funded by Hoffmann-La Roche (Nutley, N.J.) compared the absorption ability of chitosan versus orlistat (Xenical). Healthy volunteers were given either 120mg of orlistat three times daily or 890mg of chitosan three times daily for seven days, and then the groups were crossed-over. The fecal fat was analyzed in each group, and orlistat was found to significantly absorb fat (measured by increased fat in the feces). Chitosan was found to have no effect.4 A couple of other studies found chitosan supplementation was not effective in subjects without dietary alterations.5, 6
     

    The Nutrients

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  • Chromium. Chromium is a trace mineral essential to maintaining our health, and although there is no established RDA for chromium, a deficiency is known to lead to insulin resistance and glucose intolerance. It also is estimated that 90% of Americans do not consume enough chromium daily. Chromium plays an important role in glucose metabolism, regulation of insulin levels, regulation of cholesterol levels, and controlling food cravings (especially sweet cravings).

    The estimated safe and adequate daily dietary intake (ESADDI) of chromium is 50-200mcg. Different forms of chromium have different absorption levels, and natural forms, such as those found in brewer's yeast, are more efficiently absorbed compared to chromium chloride. At the recommended dosage levels, chromium is safe and may cause occasional and mild gastrointestinal upset. However, cases of toxicity, especially with chromium picolinate, have occurred from consuming 1,200mcg or more daily.

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  • Whey Proteins. New research is showing promise for the inclusion of whey proteins in diet programs. In one study, the role of branched-chain amino acids (BCAA) and leucine was evaluated in weight management. The researchers found that a diet rich in leucine promoted fat loss and lean muscle tissue.7 Compared to egg white powder, milk protein powder and soy protein isolate, both whey protein isolate and whey protein concentrate contained the highest amount of BCAA (26 and 22.5 BCAA g/100g protein, respectively). In another study, whey protein was shown to have greater effects on satiety than casein, the other protein found in milk, by increasing the levels of appetite-suppressing substances in the body—including amino acids, and the hormones cholecystokinin (CCK) and glucagon-like peptide (GLP-1).8

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  • L-Carnitine. L-carnitine is a natural substance in our bodies that plays a role in fatty acid metabolism in the mitochondria of the cells. Because of this role, it has been theorized to increase fat metabolism and enhance exercise endurance as a supplement. However, clinical studies have shown mixed results. Some early studies have shown enhanced exercise performance with carnitine, by increasing the use of fats as an energy source. Others have shown no effect of carnitine supplements in either weight loss or exercise performance. Additionally, it seems that the body does a good job at keeping high concentrations of L-carnitine in the mitochondria, and this is not altered by supplements. There are exceptions in certain populations of people (such as vegetarians) that do not get enough of the dietary amino acid precursors lysine and methionine, which are necessary for making L-carnitine. L-carnitine has shown good results with cardiac health and blood lipids maintenance in clinical studies. It is important that supplements use the form of biologically active carnitine, "L-carnitine," rather than the "D-carnitine"? form. Typically, it is used at 2-6g servings daily, with no known side effects.

    The Botanicals

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  • Green Tea Extract. Although there is not much clinical evidence to support its weight loss claims, the pre-clinical trials on green tea extract indicate there is more than just caffeine at work when inducing a thermogenic and weightloss effect. In fact, Dulloo, et al. proved there was a synergy occurring in green tea between the caffeine and the catechin-polyphenol compounds that resulted in a thermogenic effect larger than what could be attributed to either of the two types of compounds alone.9 Green tea extract also has been shown to have a weight loss effect in mice, and to reduce serum lepin levels. Lower levels have a downward effect on regulating weight regulation.

    Another possible role that green tea may play in the body's weight regulation could be in cortisol control. Recently, theanine, a unique amino acid in green tea, exhibited the ability to alter the "alpha"? waves of the brain, believed to promote relaxation and creativity. A result of these studies is that theanine is being marketed as an anti-stress and anti-cortisol supplement. According to Shawn Talbott, Ph.D., author of The Cortisol Connection: why stress makes you fat and ruins your health- and what you can do about it, stress and cortisol production is a factor in weight loss that many people do not consider.10 Essentially, Talbott contends that elevated stress leads to excess cortisol production in our bodies, leading to signs of early degenerative disease, including extra body fat, and a drop in energy levels and sex drive. Dosage recommendations for green tea extract are 125-500mg/day of an extract that is standardized to at least 60% polyphenols and/or EGCG as a marker compound.

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  • Garcinia cambogia and Hydroxycitric Acid. Hydroxycitric acid (HCA) is the main active ingredient extracted from the rind of the fruit called Garcinia cambogia, from India and Southeast Asia. While HCA formulations are promoted for their role in weight loss, appetite suppression, fat oxidation and increasing energy levels, clinical studies have yielded mixed results.

    HCA inhibits an enzyme needed for the conversion of carbohydrates into fats in the cells, called citrate lyase. HCA is thought to work for weight loss under specific conditions: since it works by blocking the conversion of carbohydrates into fats, it is thought to be best for people who binge on carbohydrates, or for those people who have high-carbohydrate diets. When carbohydrate conversion is blocked in this type of diet, the body's glycogen stores are full, while carbohydrate oxidation is maximized. In these conditions, HCA is thought to have the side benefits of suppressing appetite and increasing energy.

    A recent study published in the Journal of the American Medical Association (JAMA) found that Garcinia was not able to promote weight loss beyond the effect of a low-calorie, high-fiber diet. However, the study has been criticized on several criteria, including not using it for a high-carbohydrate diet, the conditions thought necessary for HCA to work.11 Garcinia formulations usually are recommended at the dosage of 750-1500mg daily in divided doses, standardized to 50% (or more) HCA and taken approximately 30-60 minutes before eating.

    While a magic weight loss formula has yet to be invented, we have more tools than before to control weight and body mass. Science will continue to uncover effective ingredients to be used to shape our health and body images as we like.
     

    References:

    1 Nagao T, et al. 2000. Dietary diacylglycerol suppresses accumulation of body fat compared to triacylglycerol in men in a double-blind controlled trial. J Nutr; 130:792-797
    2 Han LK, et al. 1999. Reduction in fat storage during chitin-chitosan treatment in mice fed a high-fat diet. Int J Obes Relat Metab Disord; 23(2):174-9
    3 Gades MD, et al. 2002. Chitosan supplementation does not affect fat absorption in healthy males fed a high-fat diet, a pilot study. Int J Obes Relat Metab Disord; 26(1):119-22
    4 Guerciolini R, et al. 2001. Comparative evaluation of fecal fat excretion induced by orlistat and chitosan. Obes Res; 9(6):364-7
    5 Pittler MH, et al. 1999, Randomized, double-blind trial of chitosan for body weight reduction. Eur J Clin Nutr; 53(5): 379-81
    6 Ho SC, et al. 2001. In the absence of dietary surveillance, chitosan does not reduce plasma lipids or obesity in hypercholesterolaemic obese Asian subjects. Singapore Med J; 42(1):006-10
    7 Layman DK. 2003. The role of leucine in weight loss diets and glucose homeostasis. J Nutr; 133(1):261S-267S
    8 Hall WL, et al. 2003. Casein and whey exert different effects on plasma amino acid profiles, gastrointestinal hormone secretion and appetite. Br J Nutr; 89(2):239-48
    9 Dulloo AG, et al. 2000. Green tea and thermogenesis: interactions between catechin-polyphenols, caffeine and sympathetic activity. Int J Obes Relat Metab Disord; 24(2):252-8
    10 Talbott S. 2002. The Cortisol Connection: why stress makes you fat and ruins your health- and what you can do about it. Hunter House Publishers, Alameda, CA
    11 Heymsfield, et al. 1998. Garcinia cambogia (hydroxycitric acid) as a potential anti-obesity agent: a randomized controlled trial. JAMA; 280(18):1596-600

    Sidebar 1:
    On the Web: WEIGHT LOSS

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  • www.supplementwatch.com  Weight loss ingredients

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  • www.cdc.gov/nccdphp/dnpa/obesity  The CDC Guide to Overweight and Obesity

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  • www.4woman.gov/faq/Easyread/obesity-etr.htm  Obesity info. from the National Women's Health Information Center

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  • www.obesity.org/subs/fastfacts/Obesity_Minority_Pop.shtml Obesity in minority populations

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  • www.mayoclinic.com/invoke.cfm?id=DS00314  Mayo Clinic section on obesity

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  • www.niddk.nih.gov/health/nutrit/pubs/wcycling.htm  Weight cycling, or losing the same weight over and over again

    Sidebar 2:
    Chocolate Supplements

    It just sounds too good to be true—eating chocolate and losing weight! Chocolate and cocoa extracts have been in the news lately on a number of health fronts due to their interesting chemistry and corresponding health benefits.

    It turns out there may be a reason that chocolate is the number one craved food in North America. Not only does chocolate have sugar and fat, there is a complexity of components in chocolate that elevates our mood (such as PEA, or phenylethylamine, and the cannabinoids), enhances exercise performance and thermogenesis (such as caffeine and the xanthine alkaloids) and it also has antioxidants (such as the polyphenols). Additionally, chocolate is high in magnesium and is the number one source of dietary copper in the U.S. Although there is yet little clinical evidence that taking chocolate as a supplement without the extra sugar and the fat helps in weight loss, there is building evidence that chocolate is a strong antioxidant and may help in preventing cardiovascular disease.

    Several dietary supplement companies have come up with branded products that capitalize on chocolate's potential role in weight loss by standardizing or adding in bioactive components such as bromine, caffeine, theophylline, PEA, or other compounds.
     

    Sidebar 3:
    Fiber and Satiety

    A University of California Davis study (Burton-Freeman, B, et al., 2002. Am. J. Clinical Nutrition, 2002.76:659-667) delved into a possible mechanism of why meals with higher fiber content may boost feelings of fullness in women.

    Earlier research had showed that cholecystokinin, a hormone, is released when a fat-containing food is consumed. It may be the chemical messenger that notifies the brain that the body is getting full. Fiber may trigger the same signaling mechanism.

    To better understand cholecystokinin's role, the UC Davis researchers tested how levels of the hormone respond to increases in dietary fat and fiber, and how that hormonal response corresponds to feelings of satiety.

    Test subjects were fed breakfasts that were low-fiber, low-fat; high-fiber, low-fat; or low-fiber, high-fat. Blood levels of cholecystokinin then were measured. The release of the hormone did correlate with the feelings of satiety.

    The researchers found that, in women, both the high-fat and high-fiber meals resulted in greater feelings of satiety and significantly higher levels of cholecystokinin, than did the low-fat, low-fiber meals.

    "These results indicate that the addition of fiber to a meal can increase a person's feeling of being full," said Barbara Schneeman, a UC Davis nutrition professor who led the study. "It appears this is due not only to fiber creating a greater volume of food in the gastrointestinal tract, but also to fiber promoting the release of cholecystokinin."