Solving an Ageing Problem

Traditionally, dairy-derived whey protein has been the protein source of choice for athletes and body builders, not only as is it very digestible with a high proportion of essential amino acids; it is also the richest protein source of branched-chain amino acids (BCAAs).

16/08/06 According to the United Nations, the current trend in population ageing has not been seen before in past humanity. Accompanying an increase in the proportion of older persons (over 60 years) is a decline in the proportion of the young (under age 15). By 2050, the number of older persons in the world will exceed the number of young for the first time in history; a situation that has already taken place in, more developed regions. The trend is largely irreversible and has come about as a result of the demographic transition from high to low levels of fertility and mortality1.

Increased Risk
Unfortunately, along with the dramatic change in age structure, there is evidence of a characteristic sequence of changes in dietary behaviour and physical activity patterns that leads to increased risk of chronic disease. As a result, population ageing is profoundly having major consequences and implications for all facets of human life, particularly on health and health care. In many countries there is a deficit in the infrastructure to be able to cope with the problems this transition to an older population will bring. One way of minimising this oncoming burden would be to focus on nutritional status, which has a major impact on disease and disability. It must be stressed that elderly adults are a mixed group with some very strong and some very frail individuals, but common to all is a decrease in the body’s ability to balance its own constant state. In nutritional terms, this means that although total energy intake declines with age, requirements for many nutrients increase to maintain organ systems with declining functionality2. It is therefore more difficult for the elderly to meet their nutrient requirements than younger adults and the selection of nutrient-dense foods becomes of even greater importance.

Loss of Mass
A variety of problems contribute to the development of frailty including loss of appetite and illness but the one of focus in this article is loss of lean body mass also known as sarcopenia. This term denotes the dramatic loss of muscle mass and strength during ageing. This striking feature of age related decline was deemed important enough to have its own name as not only does it impact on movement and overall nutrient intake but also independence and even breathing3, 4. An age-related phenomenon, loss of lean muscle mass can start as early as 30 years in men but occurs more rapidly in post-menopausal women reaching about 20% in both sexes at 70 years of age5. However sarcopenia is exacerbated by a sedentary lifestyle, nutritional factors and chronic disease. In healthy adults, the musculoskeletal system makes up about half of the total body weight (slightly less in women) with the total number of muscle fibres largely inherited. Resistance training can greatly increase human muscle mass, especially when combined with protein supplementation because protein is the major component of muscle. The most effective method for promoting muscle growth is to consume protein directly after exercise rather than ingesting the same meal hours later6.

Protein of Choice
Traditionally, dairy-derived whey protein has been the protein source of choice for athletes and body builders, not only as is it very digestible with a high proportion of essential amino acids; it is also the richest protein source of branched-chain amino acids (BCAAs). This group of amino acids are particularly conducive to muscle growth and regeneration as they increase the rate of protein synthesis and decrease the rate of protein breakdown in human muscle7. When combined with resistance training, whey protein has been shown to increase muscle mass and strength and encourage quicker recovery from muscle fatigue. Recent research clearly shows that protein adequacy is critical for maintaining functional status with age. Studies suggest that protein requirements to reduce the decline in muscle and bone mass with ageing in older individuals may be greater than previously thought, with safe recommended protein intakes for older man and women at 1.0-1.25g high quality protein/kg/d as opposed to the 0.8g/kg/d for adults8.

Combining Beneficial Elements
The best intervention therefore to increase muscle strength in the frail elderly would be to combine exercise with nutritional supplementation9. There is data supporting the usefulness of resistance training alone to reduce loss of lean muscle mass, but this type of exercise is not always possible for those compromised by physical disability. However dietary protein supplementation is easy to administer and relatively low cost and a recent study by Paddon-Jones et al. concluded that ingestion of 15g of whey protein per day in elderly subjects stimulated muscle protein synthesis10.

In addition Dangin and co-workers recommend the use of whey protein over other protein sources for the elderly as it is easily and quickly digested and demonstrated to show better muscle protein synthesis10. From a practical viewpoint, whey proteins can be used in a wide array of applications from nutritional bars and drinks to dairy goods such as yoghurts and ice creams. The Volactive Ultra Whey range of whey protein ingredients are produced using gentle low temperature and pressure membrane filtration technology ensuring that the protein remains in its native state. This aids whey protein’s superior solubility across the pH range and translucent quality particularly in acidic beverages, such as juice-based drinks. In addition, it ensures a bland odour and flavour profile, an attractive quality of whey proteins over other protein sources when included in food products.

The global trend in ageing is not going to go away and there is a large untapped requirement for whey protein fortified bars, drinks and supplements ranging from clinical products for hospitalised patients, to those everyday products for the healthy elderly to consume simply after taking a form of exercise, or as part of their day to day nutrition.

The author, Dr. Naomi Grant is Technical Product Manager for Food Ingredients at Volac. www.volactive.com

References
1. United Nations. (2002) World Population Ageing 1950-2050 (2002), Population Division, DESA, United Nations
2. Bales, C. and Ritchie, C.S. (2002) Sarcopenia, weight loss and nutritional frailty in the elderly. Annual Reviews Nutrition 22: 309-323
3. Gariballa, S.E. and Sinclair, A.J. (1998) Nutrition, ageing and ill health. British Journal of Nutrition 80: 7-23
4. Rosenberg, I.H. (1997) Sarcopenia: origins and clinical relevance. Journal of Nutrition 127: 990S-991S
5. Cohn, S.H., Vartsky, D., Yasumura, S. et al. (1980) Compartmental body composition based on total-body nitrogen, potassium and calcium. American Journal of Physiology 239: E524-E530
6. Wackerhage, H. and Rennie, M.J. (2006) How nutrition and exercise maintain the human musculoskeletal mass. Journal of Anatomy 208: 451-458
7. Layman, D.K. (2003) The role of leucine in weight loss diets and glucose homeostasis. Journal of Nutrition 133: 261S-267S
8. Tucker, K.L. and Buranapin, S. (2001) Nutrition and aging in developing countries. Journal of Nutrition 131: 2417S-2423S
9. Bonnefoy, M., Cornu, C., Normand, S. et al. (2003) The effects of exercise and protein-energy supplements on body composition and muscle function in frail elderly individuals: a long-term controlled randomized study. British Journal of Nutrition 89: 731-738
10. Paddon-Jones, D. Sheffield-Moore, M. Katsanos, C.S., et al. (2006) Differential stimulation of muscle protein synthesis in elderly humans following isocaloric ingestion of amino acids or whey protein. Experimental Gerontology 41: 215-219
11. Dangin, M., Guillet, C., Garcia-Rodenas, C., et al. (2003) The rate of protein digestion affects protein gain differently during aging in humans. Journal of Physiology 549: 635-644.