The foods and supplements industries have significant roles to play as nations the world over seek solutions to the obesity epidemic. Todd Runestad and Dr Susan Lawlor investigate promising areas of research
If you take in more calories than you expend, the extra calories are stored as fat. As simple as that — that?s the way people become overweight.
And in about as many ways as there are that lead to the sum of that problem are targets to shoot at: high-sugar drinks, junk-food vending machines in schools, oversized serving portions, nutrient-poor and calorie-rich foods, a crushing lack of individual willpower.
An estimated 300 million people around the world are obese (BMI>30). In the US, 31 per cent of adults are obese, a doubling in the last 20 years. Worse, 42 per cent of US high schoolers (at least those in Alaska and Missouri) are overweight or obese, a quadrupling over the past 30 years.1 Total US private insurance spending for obesity rose from two per cent in 1987 to 11.6 per cent in 2002.2
Obesity is different from overweight. People who are overweight have excess body weight, which can come from fat, muscle, bone and/or water retention. People who are obese have an abnormally high, unhealthy proportion of body fat.
The International Obesity Task Force, based in London, estimates that obesity levels will continue to rise in the early 21st century, with severe health consequences, ranging from diabetes,3 to cardiovascular disease,4,5 to various cancers,6 to poor bone health,7 and even dementia in later years.8
Whether or not you assign blame to the food industry, there are myriad signs that mainstream suppliers and manufacturers have at their immediate disposal the technologies and ingredients to make healthier food choices easier for consumers.
Will anybody take the bait?
In the post-ephedra world, supplements company offerings to address quick weight-loss solutions are lean. Citrus aurantium holds promise because it works in a similar way to ephedra, but it is receiving at least its share of pot shots precisely because of this.9Hoodia gordonii, the African satiety botanical, is probably the sexiest herb going, and if it can overcome supply issues it could be the next big thing.10 Green tea and its chemical constituents, namely EGCG, is receiving research attention as a thermogenesis aid.11 And, interestingly, a recent study showed that über-ingredient omega-3 fish oils reduced accumulation of body fat in animals fed a high-fat diet.12
The following section delves into the science of satiety. Following that are new ingredients and technologies being developed and marketed by leading science-based companies worldwide.
Satiety solutions offer opportunities
With various fashionable regimens such as the Atkins and South Beach diets losing momentum, the new buzzword is ?satiety.? This growing interest in controlling appetite for improved weight management presents opportunities for manufacturers of functional foods and beverages.
Satiety is commonly referred to as the feeling of ?fullness,? or a reduction in the desire to eat after a meal. The duration of the satiety response determines how long after eating that the feeling of fullness lasts. The link between satiety and weight management is obvious — the greater the feeling of fullness after eating, the lower the likelihood of snacking between meals.
However, the mechanism of satiety is complex. In response to food intake, the upper intestine releases specific hormones and peptides. These act upon gastrointestinal or hepatic receptors that relay messages to the brain, primarily the hypothalamus, and thus influence satiety.
Appetite-suppressing peptides include cholecystokinin (CCK), gastric inhibitory peptide (GIP), and the hormone glucagonlike peptide-1 (GLP-1), which also reduces energy intake.13 Greater stomach fullness and higher concentrations of CCK and GLP-1 are associated with lower subjective hunger ratings and lower food intake.
CCK is a hormone released when digested fats and proteins are present, and it reduces food intake. CCK stimulates enzyme secretion in the pancreas. The process eventually leads to inhibiting gastric emptying of the stomach?s foods, thereby causing gastric distension. It has been suggested that increased gastric distension, induced by the slowing of gastric emptying, may be the method by which CCK reduces food intake.14
In particular, CCK has a dose-dependent effect on appetite; one study showed a 63 per cent reduction in intake,15 although other studies are equivocal.16 Notably, a recent study showed CCK?s suppression of food intake is indeed enhanced when the stomach is distended.17 During GLP-1 infusion, hunger and prospective food consumption are lower than during saline infusion.18 GLP-1 is believed to adjust stomach and gut motility after food ingestion.
All foods are not equal
While all foods induce satiety to a certain extent, the issue of interest to diet-conscious consumers and health-orientated manufacturers is those foods that are more likely to prolong the satiation effect. However, satiety is a conditioned reflex, which can be affected by the mood of the individual, plus the flavour, odour and texture of the food. All of these factors make satiety potentially difficult, but not impossible, to measure accurately.
Common methods for measuring satiety qualitatively include examining a hunger level or ?fullness? rating, or quantitatively by visual analogue scores, by measuring the hormones mentioned above and by monitoring energy intake.
Using these techniques, clinical trials have indicated that protein produces greater satiety than other macronutrients such as carbohydrates or fat.19,20,21 For manufacturers of functional foods and beverages, this knowledge is fundamental for formulating effective weight-management products.
The power of protein
Following the rise and fall in popularity of the Atkins and other ?high-protein? diets in the last few years, the role of protein in weight-management regimens has been well publicised. Studies have demonstrated that a slight increase in protein intake — up to about 1.5 times the recommended daily allowance — appears to have an advantage over calorie-restricted diets in that it facilitates increased loss of body fat while reducing the proportion of lean tissue loss.22,23,24,25
Now, the move toward satiety-inducing products provides an opportunity to harness the beneficial effects of a ?higher protein? diet, while eliminating health concerns relating to the high-fat, low-fibre and low-vitamin content of diets such as Atkins and South Beach. For the purposes of measuring satiety, dietary proteins can be split into two categories — ?fast-digesting? and ?slow-digesting.? Studies have shown that fast-digesting proteins, such as whey proteins, are more satiating than slow-digesting proteins, such as casein,26 and as a result are more likely to be effective ingredients in satiety-inducing products.
Furthermore, whey proteins contain glycomacropeptide, which has been shown to stimulate the release of the appetite-suppressing hormone cholecystokinin in the duodenum.17
The versatile texture, solubility and neutral taste of fast-digesting whey protein products, coupled with their low-fat and low-carbohydrate content, make them suitable for a wide range of satiety-inducing applications. These include ice cream, yoghurts and mousses, in addition to bars and beverages.
Innovation in applications
While consumers want products with added functionality, they are not willing to sacrifice taste and flavour to achieve this. So, the most desirable protein ingredients have a neutral taste to guarantee a clean-flavoured end product.
In addition, the ideal choice of protein for weight-management products may differ according to the application. For example, nutrition bars benefit from protein ingredients that impart a soft, chewy texture, while ready-to-mix beverages demand protein ingredients with high solubility. These properties are inherent in whey proteins.
Now, as the industry expands beyond beverages and bars, there is an opportunity for manufacturers in new sectors to add protein to their products, and additional product attributes have come into play. This can be seen in the production of high-protein ice creams or dairy desserts, which require protein ingredients with good foaming or whipping ability and slow meltdown characteristics.
Beyond proteins, other studies show that long-chain fatty acids are more effective in releasing CCK than are short-chain fatty acids.27
Also, some research has focused on leptin, a peptide hormone that influences the storage of body fat and also acts on the hypothalamus to affect food consumption. Plasma leptin concentrations correlate positively with total body fat stores in humans.28 In one intervention study, 30 obese men following a weight-loss regimen had reduced appetite during 12 weeks of recombinant leptin injections.29 Finally, a recent study hinted at the idea that dietary fructose leads to lower insulin and leptin concentrations, which may contribute to a higher energy intake.30
In an increasingly competitive functional foods market, the pressure is on manufacturers to innovate. With growing interest in satiety, it is possible that the next wave of effective weight management functional foods will be those that help induce this feeling of satisfaction.
Protein is more satiating than fat and carbohydrates. A study published in July 2005 demonstrated that an increase in dietary protein from 15 per cent to 30 per cent of energy and a reduction in fat from 35 per cent to 20 per cent, at a constant carbohydrate intake, produced a sustained decrease in calorie intake and resulted in significant weight loss among 19 subjects.31 Clearly, protein sources and satiety ingredients will lead the way in food product launches in the immediate future.32
Solae soy protein provides greater satiety compared to diets where average amounts of protein are consumed even when the amount of carbohydrate consumed is held constant. More significantly, the higher protein diet leads to greater weight loss. In one randomised, controlled study, 90 overweight or obese subjects ate a high soy protein, low-fat diet with or without a guided physical activity program for six months. Compared to controls, the soy eaters had significantly improved body composition, losing fat but preserving muscle mass.33
?Diets high in soy protein lead to equivalent weight loss, but have the unique heart health benefits of lowering blood LDL and total cholesterol and triglycerides above and beyond what other protein sources in the diet can do,? says Greg Paul, PhD, director of nutrition at The Solae Company.
Glanbia Nutritionals has introduced Provon, a whey protein isolate containing more than 90 per cent protein. Provon contains high levels of glycomacropeptides, which are biologically active peptides that have been shown to stimulate the feeling of fullness.34 Its texture and solubility make it suited for dairy products, desserts, powdered beverage mixes, bars and snacks.
Vivitas, a Canadian supplements company, developed a satiety aid derived from potato protein (Solanum tuberosum), which promotes the release of cholecystokinin to slow the stomach from emptying. In one study, unveiled at the North American Association for the Study of Obesity, researchers reported that hunger ratings were significantly lowered by 30 per cent.
DSM and LTP in July launched Fabuless, a natural ingredient consisting of a structured system of lipids comprised of palm and oat oil fractions that maintains the feeling of satiety longer when consumed together with normal food.
The effect of Fabuless has been verified in four published placebo-controlled, double-blind studies. In two studies, after 59 healthy volunteers consumed Fabuless in a yoghurt meal, they ate 12.5 per cent and 14.2 per cent less food at a subsequent meal four hours later.35,36 A follow-up study found decreased food intake two meals later, meaning the participants did not binge eat after eating less at the first meal.37
Fabuless can be incorporated into yoghurt, milk drinks, soups, nutritional beverages, meal replacement products and ready prepared meals. Its dietary supplement form has been launched in the US market by GNC under the brand name Olibra.
National Starch Food Innovation is publishing this month High Amylose Corn Resistant Starch Monograph, a comprehensive review of 121 published nutritional studies on the effect of high-amylose resistant starches in the diet. In one representative study, subjects who ate one meal per day that contained resistant starch burned 10-25 per cent more fat, and the fat-burning increase was sustained throughout the day.38
The company?s Hi-maize ingredient seems to move fat to the top of the list to be burned for energy, at low levels, before it has a chance to be stored. Hi-maize can be used to replace fibres in breads, pasta, cookies and bars. It also helps maintain healthy blood-sugar levels.
GTC Nutrition has an oat bran ingredient, Natureal, based on short-term studies showing increased satiety with low-glycaemic index vs high-glycaemic index foods.39 The elevated viscosity inherent in oat beta-glucan retards stomach emptying. This retards the entrance of the food in the small intestine, thus prolonging digestion and absorption. Natureal is aimed at bakery, confectionery, meal replacement and cereal products.
Who will pick up the mantle of a weight-loss silver bullet pill post-ephedra? Companies are conducting research to vouchsafe their ingredient launches, ever mindful that ingredients that increase the metabolic rate are immediately seen as kin to ephedra and are thus suspect to regulatory bodies.
InterHealth has tried to learn the lessons from previous human studies showing mixed efficacy for weight loss with hydroxy-citric acid, an extract from the Garcinia cambogia plant. In animals, it has been shown to suppress fat production and reduce food intake, resulting in weight loss.41 The company formulated Super CitriMax with higher doses and reportedly increased bioavailability.
In an eight-week, randomised, placebo-controlled human clinical study, 60 moderately obese subjects taking 2,800mg/day had significant weight loss, increased fat burning, lower body mass index, as well as lower total cholesterol and higher HDL cholesterol levels. A third arm of the trial used a formulation of Super CitriMax along with its branded chromium nicotinate, ChromeMate, and Gymnema sylvestre extract, and subjects saw slightly better results.42
Pharmachem Labs has taken a starch neutraliser extract of white bean (Phaseolus vulgaris), branded as Phase 2, which has been shown to inhibit the digestive enzyme alpha-amylase. This activity prevents to some degree the digestion of complex carbohydrates, promoting weight loss. In an eight-week, randomised, double-blind, placebo-controlled human trial, 50 obese adults received either 1,500mg Phase 2 or placebo twice daily with meals. The Phase 2 group lost an average of 3.79lbs compared with the placebo group, which lost an average of 1.65lbs.43
The food world today is experiencing a renaissance in innovation. The low-carb fad and its ?net carbs? labelling paved the way for fibres and polyols. Look for new and novel fibres as well as new alternative sweeteners in the future. Indeed, there have reportedly been more new product launches in the area of modified carbohydrates in the first half of 2005 than in 2000-04 combined.
The low-carb trend was always a US phenomenon, whereas the rest of the world was gaining comfort with the notion of the glycaemic index. As the concept is simplified — say, high fibre and no sugar equals low GI — and gains greater traction, foods with components that are digested more slowly and thus provide greater degrees of satiation are sure to take hold.
So while scapegoats will be made of sugar-laden soft drinks, sedentary lifestyles and government subsidies of unhealthful ingredient industries, ultimately, what one puts in his or her mouth will have some influence on how much a person weighs. Better-for-you functional ingredients and science-based supplements are natural allies in the battle of the bulge.
Dr Susan Lawlor, who contributed to the section on satiety, is clinical nutritionist at Glanbia Nutritionals, a division of Glanbia plc, a supplier of science-based nutritional solutions for functional foods, clinical, infant and sports nutrition and nutritional supplements. www.glanbianutritionals.com
Todd Runestad is science editor at FF&N.
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