The study, by researchers from the Complutense University of Madrid and Danone Vitapole, reports that prematurely ageing mice eating an antioxidant-enriched biscuit in addition to a normal diet had improved immune system function.
"In the present study, ingestion of a diet supplemented with two different doses, five per cent and 20 per cent, of biscuits enriched with nutritional amounts of several antioxidants such as vitamins C and E, beta-carotene, zinc, and selenium improved the investigated immune functions in non-prematurely ageing mice (NPAM) and especially in prematurely ageing mice (PAM)," wrote lead author Carmen Alvarado in the journal Nutrition (Vol. 22, pp. 767-777).
As the human body ages, its ability to fight infection decreases, leading to an increased risk of infectious and degenerative diseases and ultimately affecting lifespan.
White blood cells (leukocytes) help the body to fight infection and between four and 11 billion cells is indicative of a healthy immune system. However, the function of white blood cells is reported to be strongly influenced by the antioxidant/oxidant balance, and ageing results in higher levels of so-called oxidative stress.
As part of their normal function, leukocytes produce reactive oxygen species (ROS) and, therefore, maintaining antioxidant levels of these cells is very important to sustain a healthy immune system.
While some data are available in the literature for antioxidants on markers for ageing, the researchers said that very limited data are available on the effect of supplementation of the diet with mixtures of antioxidants.
To test their hypothesis that antioxidant supplementation can improve the oxidative stress levels experienced by leukocytes by ageing, the researchers randomly divided NPAM and PAM into control and experimental (supplemented groups). The experimental groups were supplemented with either five or 20 per cent of antioxidant-enriched biscuits (Danone Vitapole). The biscuits are commercially available to consumers.
After 15 weeks of eating these diets, Alvarado and her colleagues measured leukocyte functions (such as chemotaxis, phagocytosis, and natural killer activity, lymphoproliferation and interleukin-2 release), antioxidant defences, and lipid and DNA oxidative damage levels.
It was found that the effect of antioxidants was more pronounced in the PAM than the NPAM group, and that 20 per cent supplementation was better than five per cent.
When comparing the PAM control group and the two PAM supplemented groups, the researchers found that addition of the antioxidant-enriched biscuits to the diet of the mice was associated with significantly improved activity of the immune system.
The authors note that all the antioxidants used in the biscuits have previously been shown to have enhancing effects on different immune system function in both animals and humans.
"Because the immune function is a marker of health and several of the immune parameters studied are predictors of longevity, our data strongly indicate, on the one hand, the importance of maintaining a proper regulation of redox homeostasis in immune cells to preserve their functions and, on the other hand, that the biscuits enriched with nutritional doses of several antioxidants used in the present work appear to be a functional food that allows improvement of leukocyte function through restoration of the redox balance of these cells," concluded Alvarado.