Health benefits of fruit and vegetables are from additive and synergistic combinations of phytochemicals

Abstract

Cardiovascular disease and cancer are ranked as the first and second leading causes of death in the United States and in most industrialized countries. Regular consumption of fruit and vegetables is associated with reduced risks of cancer, cardiovascular disease, stroke, Alzheimer disease, cataracts, and some of the functional declines associated with aging. Prevention is a more effective strategy than is treatment of chronic diseases. Functional foods that contain significant amounts of bioactive components may provide desirable health benefits beyond basic nutrition and play important roles in the prevention of chronic diseases. The key question is whether a purified phytochemical has the same health benefit as does the whole food or mixture of foods in which the phytochemical is present. Our group found, for example, that the vitamin C in apples with skin accounts for only 0.4% of the total antioxidant activity, suggesting that most of the antioxidant activity of fruit and vegetables may come from phenolics and flavonoids in apples. We propose that the additive and synergistic effects of phytochemicals in fruit and vegetables are responsible for their potent antioxidant and anticancer activities, and that the benefit of a diet rich in fruit and vegetables is attributed to the complex mixture of phytochemicals present in whole foods.

Antioxidant activities of the extracts from chestnut flower, leaf, skins and fruit

“…Nevertheless, those assays were carried out using whole extracts instead of individual compounds. According to Liu (2003), additive and synergistic effects of phytochemicals in fruits and vegetables are responsible for their potent bioactive properties and the benefit of a diet rich in fruits and vegetables is attributed to the complex mixture of phytochemicals present in whole foods. This explains why no single antioxidant can replace the combination of natural phytochemicals to achieve the health benefits.…”

Influence of habitual diet on antioxidant status: a study in a population of vegetarians and omnivores

“…These carotenoids have been found to exhibit anti-carcinogenic and anti-atherogenic properties as reviewed previously (Mayne, 1996;Palace et al, 1999), although it should be noted that randomized intervention trials with relatively high doses of individual carotenoids fed in isolation have shown an increased risk of some chronic diseases (Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group, 1994;Omenn et al, 1996). Nonetheless, the combined effects of increased levels of various carotenoids could have significant biological effects, as it has been suggested that several phytochemicals in combination may have a better protective effect than their individual parts (Liu, 2003). The increased plasma carotenoids, resulting mainly from the increased vegetables intake in vegetarians could also reflect elevated levels of 'other' phytochemicals in blood/body, which have not been measured in this study, including polyphenols, phyto-oestrogens and organosulfer compounds that are thought to have antioxidant as well as other biologically important properties (Kris-Etherton et al, 2002).…”

Enhancing antioxidant activity, microbial and sensory quality of mango (Mangifera indica L.) juice by γ-irradiation and its in vitro radioprotective potential

“…Mango is an excellent source of β-carotene (provitamin A carotenoid), vitamin C and polyphenolic compounds with traces of vitamins E, K and B. These bioactive compounds are good antioxidants and their daily intake in the diet has been related to prevention of degenerative processes such as cardiovascular diseases and cancer (Liu 2003). Thus, consumption of mango could provide significant amounts of bioactive compounds possessing antioxidant activity in the human diet.…”