Biology of Ageing and Role of Dietary Antioxidants

The interest in relationship between diet and ageing is growing and research has shown that dietary calorie restriction and some antioxidants extend lifespan in various ageing models.

image of young jumping superimposed on old person

On the one hand, oxygen is essential to aerobic organisms because it is a final electron acceptor in mitochondria and therefore required in the provision of cellular energy

Reactive oxygen species in ageing

On the other hand, oxygen is harmful because it can continuously generate reactive oxygen species (ROS), which are believed to be the factors causing ageing of an organism due to the redox reaction causing oxidative stress.

To remove these ROS in cells, aerobic organisms possess an antioxidant defense system which consists of a series of enzymes, namely, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR).

Antioxidant protection against ROS in ageing

In addition, dietary antioxidants including ascorbic acid, vitamin A, vitamin C, α-tocopherol, and plant flavonoids, as well as supplemental antioxidants are also able to scavenge ROS in cells and therefore theoretically can extend the lifespan of organisms.

In this connection, various antioxidants including tea catechins, theaflavins, apple polyphenols, black rice anthocyanins, and blueberry polyphenols have been shown to be capable of extending the lifespan of fruit flies. It may well prove to be the case in humans also.

The free radical theory in ageing

One of the most widely accepted theories proposed to explain ageing is the free radical theory, according to which oxygen-derived free radicals cause age-related impairment through oxidative damage to biomolecules, with mitochondria being the main target of free radical attack.

Since oxygen radicals are needed for many metabolic and physiological processes, an equilibrium between radical production and their antioxidant-linked inactivation is required to preserve health. Thus, senescence is the result of an imbalance between free radical production and antioxidant defences, with concomitant oxidative stress and age-dependent functional decline.

The use of free radicals by the immune system.

This process is especially evident in the immune cells, which use free radicals in their functions and suffer a senescent deterioration probably linked to oxygen stress.

Conversely, several laboratories, have shown that antioxidants preserve an adequate function of immune cells against homeostatic disturbances caused by oxidative stress, such as that involved with age.

Cartoon drawing of family gathering from young to old

The immune system as an indicator of health.

Therefore, since the immune system is an indicator of health and a longevity predictor, the protection of this system afforded by dietary antioxidant supplementation may play an important role in order to achieve a healthy ageing.

Dr. Stephen Bray

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