Nutrition, longevity and lifestyle

Nutrition and longevity

Lifespan is somehow related to the amount of food energy consumed: this was first systematically investigated in the seminal study by Weidruch et al (1986).

A simplistic pursuit of this principle of caloric restriction followed, involving research into longevity of those who simply reduced their food energy intake. Perhaps not suprisingly, people found that cutting down on food reduced their quality of life so considerably as to negate any possible advantages of lengthening their lives.

Underlying this research was the hypothesis that oxidative damage was the agent which accelerated aging, and that aging was retarded when the amount of carbohydrates was reduced through dietary restriction.

However, recent research has produced increased longevity in animals (and shows promise for increased human longevity) through the use of insulin uptake retardation. This was done through altering an animal's metabolism to allow it to consume similar food-energy levels to other animals, but without building up fatty tissue. (Bluher et al, 2003)

In effect, it is now thought that the agent which increases longevity is leanness in animals, and that it is the accumulation of fatty tissue over the years which may gradually and inevitably reduce life expectancy.

This has set researchers off on a line of study which presumes that it is not low food energy consumption which increases longevity. Instead, longevity may depend on an efficient fat processing metabolism, and the consequent long term efficient functioning of our organs free from the encumbrance of accumulating fatty deposits. (Das et al, 2004)

Lifestyle and nutritional needs

Adequate nutrition contributes to three outcomes which are necessary for the organism’s normal functioning.

These are:

• Adequate energy levels
• Maintaining proper body structures and processes, e.g. muscle function, immune protection, bone density and strength
• Repair and development of all of the organism’s systems.

In the case of humans, ‘normal functioning’ is affected by a range of situations, which are often open to choice. A weightlifter, labourer, Inuit fisherman, Sumo wrestler, clerical worker, infant and bed-bound person will all have different definitions of ‘normal functioning’, they all have different body shapes and sizes, and their nutritional needs will vary also.

Consequently, suitable nutrition varies according to each individual’s situation, and to some extent on the choice of lifestyle. Athletes may need high levels of protein and energy to enable high performance and repair for the high stresses on their body. People working hard in a cold environment may need high fat levels in their diets, to help maintain normal body temperature. This beneficial high fat level may be very harmful for people in other situations, eg a sedentary worker in an air-conditioned office.

So the aim of good nutrition in terms of body maintenance, repair and functioning will be often relative to the choices and circumstances of the individual.

However, the holistic model of nutrition points out that for example high energy needs can be met in various ways, some more healthful than others. Food energy can be obtained from most foods, and are probably best obtained from those foods which have as high a concentration of other nutrients as possible.

Thus although nutrition and food types vary widely according to lifestyles and situations, nevertheless within each different set of requirements the principles of good nutrition can still be applied.