he berry from the acai palm tree (Euterpe oleracea) is native to South America where it is used by the natives as a food and medicine. Analysis of the berry shows that it contains a rich cocktail of antioxidant chemicals which may explain its efficacy as a health tonic and medicine in South American culture. However, compared to other plant foods with high contents of antioxidants such as olives, relatively little is known about the effects of the acai berry on health. To date, the studies that have been performed have looked at whole pulp extract from the berry, and used it to investigate potential hypocholesterolaemic effects. For example in one study1, researchers fed rats a diet designed to increase serum cholesterol levels and then supplemented their diet with the acai berry at 2% dry weight for 6 weeks. The total and non-high density lipoprotein fraction of cholesterol increased in the rats, but this effect was ameliorated by addition of the acai berry extract.
In the same study, the researchers measured the levels of carbonyl proteins and protein sulfhydryl groups as a measure of oxidative stress and found that levels in plasma were reduced with acai berry supplementation. In addition the acai berry also caused an increase in the plasma levels of superoxide dismutase in the rats supporting the contention that reductions in oxidative stress may account for the cholesterol effects seen. Other studies have investigated content of the acai berry and found high concentrations of antioxidants in the fruit. For example, in one study2, researchers identified the polyphenols homoorientin, orientin, isovitexin, cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside from the fruit extract. Cell culture experiments3 have shown that acai flavonoids (catechin and epicatechin) as well as the phenolic constituents of the pulp extract (p-hydroxybenzoic, vanillic, syringic and ferulic acids) are transported across Caco-2 cell monolayers, suggesting bioavailability in humans.
However, although oxidative stress is present in the dyslipidaemia seen in abdominal obesity, controversy surrounds its involvement. This is largely because the free radical production associated with abdominal obesity may be a symptom and not the cause of the disorder. Adipocytes for example, release cytokines and increase oxidative stress when they proliferate and grow and this is likely the cause of the association between oxidative stress and central obesity. The favourable effects of the acai berry on abnormal lipid levels may therefore be explained by other components within the fruits. This effect for example could be due to the plant sterols present, compounds that are known to have cholesterol lowering effects through inhibitory action on cholesterol transport in the gut. The effect could also be due to the presence of dietary fibre in the berries. The latter effect could be investigated through use of dietary fibre free supplements, something that has not yet been investigated.
1de Souza, M. O., Silva, M., Silva, M. E., de Paula Oliveira, R. And Pedrosa, M. L. 2010. Diet supplementation with acai (Euterpe oleracea Mart.) pulp improves biomarkers of oxidative stress and the serum lipid profile in rats. Nutrition. 26: 804-810
2Gallori, S., Bilia, A. R., Bergonzi, M. C., Barbonzi, W. L. R. and Vincieri, F. F. 2004. Polyphenolic constituents of fruit pulp of Euterpe oleracea Mart. (acai palm). Chromatographia. 11: 739-742
3Pacheco-Palencia, L. A., Talcott, S. T., Safe, S. and Mertens-Talcott, S. 2008. Absorption and biological activity of phytochemical-rich extracts from acai (Euterpe oleracea Mart.) pulp oil in vitro. Journal of Agriculture and Food Chemistry. 56: 3593-3600
