| By Peter Huth, PhD|
Director-Regulatory & Research Transfer
Dairy Management Inc. (DMI)
The awareness of functional foods is definitely on the rise, fueled by consumers' keen interest in the relationship between diet and disease prevention. These types of foods and beverages range from those that promote a healthy lifestyle to those that address a specific disease or health condition.
Dairy foods and dairy ingredients are well positioned to play a significant role in the growth of this market, with taste attributes, versatility, functionality and emerging health benefits that go beyond basic nutrition.
While many new types of dairy-based functional foods and beverages are currently in development, examples of functional dairy foods are as close as the local dairy case. Decades of research show that traditional dairy products, as part of a healthy diet, offer an array of benefits in the areas of bone health, blood pressure reduction and weight management.
Many of the nutrients in dairy foods are well known for their ability to help build and maintain strong bones. Dairy foods are also the highest contributor of potassium, a nutrient recognized for its blood-pressure-lowering effects but consumed in inadequate amounts by most Americans. This issue recently prompted the new Dietary Guidelines for Americans 2005 to recommend consumption of three cups of low fat or fat-free milk or milk products daily. Research shows that consuming three servings of dairy foods daily as part of the DASH (Dietary Approaches to Stop Hypertension) diet-a model eating plan recommended by the Dietary Guidelines-helps reduce blood pressure.
In recent years, studies in overweight and obese subjects have demonstrated that including three servings of dairy foods each day as part of a reduced-calorie diet resulted in more weight and fat loss than cutting calories alone in a diet low in dairy. The mix of nutrients found in dairy foods, especially calcium and protein, may be responsible for helping the body break down and burn fat.
With these and newly emerging nutritional benefits of traditional dairy foods, it makes sense to explore the many components of dairy. Exciting research with dairy protein components suggests that food formulators have new reasons to consider an ingredient like whey protein, derived from the natural cheese manufacturing process. And conjugated linoleic acid (CLA), a fatty acid found in dairy fat, is emerging as a bioactive lipid component with unique health benefits of its own.
Dairy Ingredients Star in Functional Foods
Whey protein, a popular ingredient in energy and performance foods and beverages, appears in numerous new products, including the following:
The Gatorade GSlide Smoothie is "uniquely designed" for growing athletes. It contains calcium and protein (from whey protein isolate) to help build strong bones and muscles. The product is available in three flavors, Strawberry, Blue Raspberry and Watermelon.
Odyssey Protein 40 energy bars by Premier Nutrition provide 40 grams of protein from a blend of whey protein isolate, hydrolyzed whey protein and soy protein isolate. The company claims the bars are ideal for post-workout recovery or as a meal replacement. It is also maltitol-free, making it easy to digest. The bars are available in Peanut Butter Chocolate Chip, Almond Brownie and Oatmeal Raisin varieties.
Although there are no approved health claims related to CLA, some dairy products in the U.S. and abroad promote their CLA content.
Natural By Nature Cheddar Cheese from Pennsylvania's Natural Dairy Products Corporation is now available in health food stores in Sharp Cheddar and Raw Mild Cheddar varieties. The organic cheeses are produced from the milk of grass-fed cows and are said to be naturally high in CLA, beta-carotene, and vitamins A and E. The exact CLA content is not provided.
La Serenisima Active Partially Skimmed Milk is sold in Argentina. The company states that the product has extra calcium as well as CLA. The milk contains .20 grams of CLA. Ingredients include partially skimmed milk, naturally concentrated calcium from milk, vitamins A and D, and CLA.
Under the Zen Linea Salute brand, Yogurt Cremoso alla Fragola is sold in Italy. It is a creamy, strawberry-flavored yogurt that the manufacturer indicates is naturally rich in CLA and omega 3 fatty acids. Offered by Techno-Foods, the yogurt product provides 46 mg of CLA.
The Whey Protein Advantage
Whey protein has many desirable functional attributes for formulating today's foods and beverages, including features such as a clean, neutral flavor, and gelling, foaming, emulsifying and browning capabilities. Nutritionally, whey protein is a high quality protein with a unique amino acid composition that may give active people a competitive edge. This makes it an ideal ingredient for sports, nutrition and energy bars, as well as drinks.
Whey protein is a complete protein containing all the essential amino acids humans need in amounts proportional to the body's protein synthetic needs. Because whey is a highly digestible protein, the amino acid components of whey reach the body's cells to permit them to make the proteins they need.
Whey protein has a high biological value compared with other proteins (i.e., 104 for whey protein vs. 100 for eggs, 74 for soy protein and 54 for wheat). Biological value is a measurement of protein quality that expresses the efficiency with which the body uses protein.
Whey protein is efficiently digested and rich in branched-chain amino acids (BCAAs). The BCAAs consist of leucine, isoleucine and valine, and are a unique class of amino acids because they can be utilized directly as an efficient fuel source for exercising muscle. They can also regulate muscle protein synthesis (especially leucine), as well as help maintain blood glucose homeostasis under conditions of intense or prolonged periods of exercise. Whey protein is the highest natural source of BCAAs, providing about 26 grams per 100 grams of protein of the BCAAs leucine, isoleucine and valine. The oxidation of amino acids-mainly BCAAs-can provide 10-15% of the total energy required during exercise.
Body builders have long looked to protein as a muscle builder. Now, emerging research is confirming that the amino acids in whey protein do in fact offer this advantage. Whey protein's BCAAs may help minimize muscle loss under conditions of increased protein breakdown; the abundance of leucine in whey plays a key role in the control of protein synthesis and appears to favorably affect the rate of muscle protein recovery after exercise. Also, whey proteins are rich in arginine and lysine, which may increase the release of a hormone that stimulates muscle growth.
Whey Protein's Health Benefits
Whey protein is more than just a source of high quality protein. It also appears to offer other health benefits, including weight management attributes, lowering blood pressure and enhancing immunity.
Emerging research suggests that diets lower in carbohydrates (>40% calories), moderate in fat (>30% calories) and higher in high quality protein (>30% calories) and their amino acid components, especially the higher amounts of leucine found in whey protein, may help overweight and obese people on a reduced-calorie diet preserve lean muscle mass, lose fat and manage blood glucose more effectively than those who just cut calories while consuming higher carbohydrates and less protein.
Preliminary studies also show that modified whey protein may help reduce blood pressure. For example, in animals, specific whey peptides inhibited the activity of angiotensin converting enzyme (ACE), which switches on a hormone that increases blood pressure by constricting vascular smooth muscle. A preliminary study in humans found that intake of 20 grams a day of a specific hydrolyzed whey protein isolate significantly reduced blood pressure in adults with borderline high blood pressure.
Components in whey protein may also help the human body protect itself against toxins, bacteria and viruses. For example, lactoferrin, an iron-binding whey protein, may increase iron absorption and transport, enhance immunity and stimulate growth of beneficial bacteria in the intestinal tract. The immunoglobulins in whey protein have shown antimicrobial activity and may help neutralize some toxins and viruses.
Preliminary indications of new health benefits from whey protein are on the horizon. Early research in animals hints that whey protein helps promote satiety by slowing the pace in which food empties from the stomach. Recently, short-term food intake studies in young men showed that whey protein significantly reduced food intake more than sugar, egg protein and water. Preliminary studies in animals also suggest that whey protein may help prevent dental caries by acting as a topical buffer to caries-promoting acid producing bacteria, while specific bioactive peptides of whey, including lactoferrin, glycomacropeptide and lysozyme appear to exert anti-cariogenic properties through inhibition of acid-producing oral bacteria (e.g., S. mutans).
CLA-Dairy's Natural Cancer Fighter
CLA represents a class of fatty acids naturally present in the fat of cow's milk and certain ruminant animal meats, particularly beef and lamb. Up to 90% of the CLA in milkfat is in the cis-9, trans-11 configuration, which, emerging research indicates, holds anti-cancer properties and could have positive effects on cardiovascular health. Research shows that endogenous synthesis of CLA in the mammary gland of dairy cattle accounts for the majority of the cis-9, trans-11 CLA present in milkfat with about 70% to more than 90% derived from the conversion of vaccenic acid (18:1,trans-11), a rumen biohydrogenation intermediate. The balance of CLA is produced through rumen biohydrogenation by converting linoleic acid to cis-9, trans-11 CLA.
The form of CLA found in milk may also be effective against many types of cancer, including skin, forestomach and colorectal. Biomedical studies using animal models have shown that the CLA in milkfat is among the most potent naturally occurring anti-carcinogens. In 1996, the National Academy of Sciences stated that "CLA is the only fatty acid shown unequivocally to inhibit carcinogenesis in experimental animals."
CLA's cancer-fighting properties have been shown in animal models of breast cancer, where it appears to help stave off cell damage and inhibit abnormal cell growth. Conducting human studies poses a particular challenge because of breast cancer's long latency period. However, a population study in Finland showed that a diet high in CLA and trans-vaccenic acid (the immediate metabolic precursor to CLA) from dairy products, especially cheese, was associated with reduced risk of breast cancer in post-menopausal women. However, another population study was unable to demonstrate CLA's anti-cancer effects. This clearly demonstrates the need for further epidemiology studies in this area.
Several animal studies and a limited number of clinical studies in humans suggest that CLA provides heart health benefits but more studies in humans are needed to confirm CLA's heart health benefits.
Increasing Dairy's CLA Content
Scientists are currently exploring methods to enhance the CLA content of milk and other dairy products to close the gap between the amount humans consume and the amount that seems to produce health benefits.
People generally consume between 140 mg and 420 mg of CLA per day, including both CLA consumed directly from dairy foods and meats, in addition to the vaccenic acid from these foods that is converted to CLA. Although researchers aren't yet sure how much CLA humans need for an anti-cancer effect, some estimate the amount to be between 700 mg and 800 mg of CLA per day.
Scientists at the dairy farmer-funded Northeast Dairy Foods Research Center at Cornell University are conducting research to understand how CLA is produced in cow's milk fat and how cows can yield milk with higher levels of CLA by modifying their diet. The research group recently tested milk with naturally enhanced levels of CLA and vaccenic acid to determine sensory characteristics such as appearance, flavor, aroma and texture, and found it comparable to standard milk in all regards.
Another objective of the Cornell research group is to produce dairy products with naturally enhanced CLA levels to use in biomedical studies with animal models of human disease. The group has produced a natural CLA-enriched butter with a CLA content about seven times greater than that of average butter. In an animal study, the CLA-enriched butter was effective in reducing the occurrence of breast cancer.
It's possible that the CLA content of cheese and yogurt could be enhanced by bacterial starter cultures, including several strains of Lactobacillus, Propionibacterium, Bifidobacterium and Enterococcus. These bacterial strains can convert linoleic acid to CLA, but further testing is required to determine if this conversion actually occurs in cheese and yogurt production.
Bright Future for Dairy Ingredients
Dairy foods and dairy ingredients have a demonstrated track record in functional foods and beverages. As research continues to elucidate the potential health benefits of dairy ingredients, such as whey protein, whey's bioactive peptides and CLA, these dairy components have the potential to play a role in new kinds of healthful dairy-based functional foods.
About the author: Peter Huth, PhD, is director of regulatory and research transfer at Dairy Management Inc. (DMI), Rosemont, Ill. DMI is the domestic and international planning and management organization that builds worldwide demand for U.S.-produced dairy products on behalf of America's dairy farmers.
*References furnished upon request.*