Long-Term Dietary Strawberry, Spinach, or Vitamin E Supplementation Retards the Onset of Age-Related Neuronal Signal-Transduction and Cognitive Behavioral Deficits

TLDR

Recent research indicates that oxidative stress vulnerability is a key driver of age‑related CNS decline and that antioxidants such as vitamin E may mitigate these effects. The study examined whether long‑term feeding of Fischer 344 rats with antioxidant‑rich diets (strawberry, spinach, or vitamin E) could prevent age‑induced receptor‑mediated signal transduction deficits that might affect behavior. Researchers measured oxotremorine‑enhanced striatal dopamine release, cerebellar β‑receptor GABA responses, striatal synaptosomal Ca²⁺ clearance, carbachol‑stimulated GTPase activity, and Morris water maze performance in rats fed control, strawberry, spinach, or vitamin‑E diets. Spinach supplementation most effectively slowed age‑related declines in all parameters except GTPase activity, where strawberry was superior, while both strawberry and vitamin E offered comparable protection on the remaining measures, suggesting that antioxidant‑rich foods can retard CNS and cognitive deficits associated with aging.

Abstract

Recent research has indicated that increased vulnerability to oxidative stress may be the major factor involved in CNS functional declines in aging and age-related neurodegenerative diseases, and that antioxidants, e.g., vitamin E, may ameliorate or prevent these declines. Present studies examined whether long-term feeding of Fischer 344 rats, beginning when the rats were 6 months of age and continuing for 8 months, with diets supplemented with a fruit or vegetable extract identified as being high in antioxidant activity, could prevent the age-related induction of receptor-mediated signal transduction deficits that might have a behavioral component. Thus, the following parameters were examined: (1) oxotremorine-enhanced striatal dopamine release (OX-K + -ERDA), (2) cerebellar β receptor augmentation of GABA responding, (3) striatal synaptosomal 45 Ca 2+ clearance, (4) carbachol-stimulated GTPase activity, and (5) Morris water maze performance. The rats were given control diets or those supplemented with strawberry extracts (SE), 9.5 gm/kg dried aqueous extract (DAE), spinach (SPN 6.4 gm/kg DAE), or vitamin E (500 IU/kg). Results indicated that SPN-fed rats demonstrated the greatest retardation of age-effects on all parameters except GTPase activity, on which SE had the greatest effect, whereas SE and vitamin E showed significant but equal protection against these age-induced deficits on the other parameters. For example, OX-K + -ERDA enhancement was four times greater in the SPN group than in controls. Thus, phytochemicals present in antioxidant-rich foods such as spinach may be beneficial in retarding functional age-related CNS and cognitive behavioral deficits and, perhaps, may have some benefit in neurodegenerative disease.