Supplement Research - Coffee Polyphenols Suppress Body Fat by Inhibiting Fat Storage Genes

By Robbie Durand, M.A.

Senior Science Editor

It has long been thought that caffeine, the active ingredient in coffee, has fat-burning effects. Several studies suggest that coffee consumption helps prevent chronic diseases, including type 2 diabetes, liver diseases, and Parkinson’s disease. These beneficial effects of coffee are attributed to caffeine, which is abundant in coffee. Scientists are now discovering that coffee also contains many phenolic compounds, otherwise known as coffee polyphenols (CPP)— such as caffeoylquinic acids acids and feruloylquinic acids. It has been reported that a 200-milliliter cup of roasted ground coffee supplies approximately 200 to 675 milligrams of CPP, and the daily intake of CPP by a coffee drinker is as much as 1 gram.

Researchers fed rats a high-fat diet, and administered the rats coffee polyphenols that were devoid of caffeine. Interestingly, the study found that long-term intake of CPP significantly suppressed visceral and liver fat accumulation that was induced by a high-fat diet, attenuated the increase in plasma glucose and insulin concentrations, and concomitantly increased energy expenditure.

Some interesting discoveries were made. Histological analysis of the adipose tissue revealed that CPP-fed mice had smaller adipocytes than mice fed a high-fat diet without CPP, which correlated with a lower number of infiltrating macrophages. Energy expenditure evaluated by indirect calorimetry was significantly increased in CPP-fed mice. CPP also downregulated lipogenic enzymes in adipose tissue.

This study demonstrates that coffee polyphenols can have an additive effect on reducing lipogenic genes, and can have added effects on fat loss.

Reference:

Murase T, Misawa K, Minegishi Y, Aoki M, Ominami H, Suzuki Y, Shibuya Y, Hase T. Coffee polyphenols suppress diet-induced body fat accumulation by downregulating SREBP-1c and related molecules in C57BL/6J mice. Am J Physiol Endocrinol Metab, 2010 Oct 13.

Watermelon Extract for Better Muscle Pumps

According to a study published in the American Journal of Hypertension, watermelon— which contains the amino acid L-citrulline— helps lower blood pressure and improves the performance of arteries by vasodilating the blood vessels.

In a small, pilot study led by food scientists at Florida State University, researchers found that eating 6 grams of watermelon extract a day for six weeks lowered blood pressure in all nine middle-aged subjects with prehypertension— elevated blood pressure, but not yet considered high blood pressure. The subjects were given a daily dose of 6 grams, or slightly more than a teaspoonful, of L-citrulline extracted from watermelons. But there is one catch— you would have to eat 1½ watermelons a day to achieve the same effect— so taking an extract is a much more realistic and practical approach.

Watermelon extract was used because watermelon is the richest edible natural source of L-citrulline, which is closely related to L-arginine, an amino acid that's essential to the regulation of healthy blood pressure. Once in the body, the L-citrulline is converted into L-arginine. Simply consuming L-arginine as a dietary supplement isn’t an option for many hypertensive adults because the therapeutic doses can cause nausea, gastrointestinal tract discomfort and diarrhea. In contrast, watermelon is well tolerated. You can take either watermelon extract or use L-citrulline; the watermelon extract contains more antioxidants and other health benefits as opposed to consuming only L-citrulline— so it’s a matter of choice for bodybuilders.

Reference:

Figueroa A, Sanchez-Gonzalez MA, Perkins-Veazie PM, Arjmandi BH. Effects of Watermelon Supplementation on Aortic Blood Pressure and Wave Reflection in Individuals With Prehypertension: A Pilot Study. Am J Hypertens, 2010 Jul 8. [E-pub, ahead of print]

DCT for Fat Loss

Capsaicin from chili pepper is known to stimulate thermogenesis through a central nervous mechanism— however, the dose that is needed to achieve this benefit causes intolerable gastrointestinal side effects. Does the term, “crapping fire” make you feel uncomfortable?!!

Studies suggest that capsinoids such as dihydrocapsiate (DCT) found in the non-pungent CH-19 sweet pepper share the positive metabolic characteristics of capsaicin, without inducing gastrointestinal side effects. DCT has a hot taste threshold— estimated at approximately 1,000 times that of capsaicin— but both capsaicin and DCT stimulate TRPV1 receptors in the gut, which bring about activation of the sympathetic nervous system (SNS)— which can increase lipogenesis and thermogenesis. Extracts of CH-19 sweet pepper have been shown to increase body temperature, oxygen consumption, sympathetic nervous system activation, and lead to weight loss in two studies.

Researchers from the University of California took 33 subjects and placed them on a very low-calorie diet (800 kcal/day, providing 120 grams of protein daily) over four weeks. The subjects were randomly assigned to receive either DCT capsules three times per day (3 mgs or 9 mgs) or placebo. At the end of the study, researchers found that DCT supplementation by overweight and obese subjects significantly increased postprandial energy expenditure— when combined with a high protein, very low-calorie diet on an outpatient basis. The increase is estimated to be equivalent to an increase in daily energy expenditure of approximately 100 kcal for a 100-kilogram individual. This is not much, but for the dieting bodybuilder even small increases in metabolic rate can mean the difference between winning and second place.

Reference:

Lee TA, Li Z, Zerlin A, Heber D. Effects of dihydrocapsiate on adaptive and diet-induced thermogenesis with a high protein very low calorie diet: a randomized control trial. Nutr Metab, (Lond). 2010 Oct 6;7:78.

Whey Protein: More Than Just A Protein

Whey protein does a whole lot more than just enhance protein synthesis. In a new study, rats were administered whey protein or casein and put through a muscle overload protocol. Researchers strapped tiny weights on the rats’ backs and made the rats jump up— similar to a person doing weighted jump squats. At the end of the study, it was found that whey protein reduced muscle damage, but also enhanced liver antioxidant levels. Interestingly, levels of ThioBarbituric Acid Reactive Substances (TBARS), a well-known biomarker of oxidative damage, are known to increase in plasma after weightlifting training; however, TBARS were lowered after whey protein consumption. Additionally, whey protein increased total liver glutathione levels. Thus, whey protein has potent antioxidant properties— both in muscle and in liver. 

Another interesting finding was that while all the rats were administered the exact same amount of protein, the whey protein group had larger increases in muscle mass. These results suggest that the potent biochemical antioxidant actions of whey protein mediated a reduction in cellular damage to both liver and muscle, resulting in enhanced muscle and bodyweight.

Reference:

Haraguchi FK, Silva ME, Neves LX, Dos Santos RC, Pedrosa ML. Whey protein precludes lipid and protein oxidation and improves body weight gain in resistance-exercised rats. Eur J Nutr, 2010 Nov 3.