Berries may reduce risk factors for metabolic disorders
Daily consumption of a range of berries, including lingonberry, sea buckthorn, bilberry, and black currant produced a 23 per cent reduction in levels of an enzyme called alanine aminotransferase (ALAT), a well-established marker of nonalcoholic fatty liver disease (NAFLD), according to findings published in the European Journal of Clinical Nutrition.
Fatty liver is reportedly on the rise in the US, with between one quarter and one half of Americans, and the prevalence of NAFLD has increased in line with the ongoing obesity epidemic.
Recent findings have also reported that metabolic syndrome, a condition characterised by central obesity, hypertension, and disturbed glucose and insulin metabolism, and linked to increased risks of both type 2 diabetes and CVD, does not develop at all without NAFLD.
Blazing a trail
The new study, led by Dr Heikki Kallio from the Department of Biochemistry and Food Chemistry at the University of Turku , is said to be the first human trial linking berries to liver function and components of metabolic syndrome.
Kallio and his co-workers recruited 31 women with an average age of 43 and randomly assigned them to one of two groups: Both groups underwent a lifestyle intervention, and one group received a supplement of 163 grams per day of lingonberry (Vaccinium vitis-idaea), sea buckthorn berry (Hippophae rhamnoides, ssp. mongolica, var. Ljubitelskaja), bilberry (V. myrtillus) and black currant (Ribes nigrum). Berries were supplied as food products and intended to replace other snacks. Five Finnish food enterprises manufactured the products, noted the researchers.
At the end of 20 weeks, ALAT levels decreased by 23 per cent in the berry group, which the researchers said could be regarded as “nutritionally significant by enhancing the liver function”.
Furthermore, levels of adiponectin increased, said the researchers. Adiponectin is a protein hormone linked to various metabolic processes, and levels are inversely related to body fat levels.
Berry good potential
“This study showed that the daily consumption of more than 150 g of northern berries in various forms as part of the normal diet had a positive affect on ALAT and adiponectin levels, but the small amount of berries consumed as part of normal diet in lifestyle group was not enough to evoke such an impact,” wrote Kallio and his co-workers.
“Present study results indicate common northern berries and berry products as an effective component of lifestyle modifications aimed at decreasing development of metabolic syndrome and subsequent complications,” they added.
According to the Finnish researchers, the berries may working via non-antioxidative mechanisms, with studies showing no influence on the total antioxidant capacity of blood, but changes to markers of inflammation.
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Source: European Journal of Clinical Nutrition
Published online ahead of print, doi:10.1038/ejcn.2010.27
“Berry meals and risk factors associated with metabolic syndrome”
Authors: H-M Lehtonen, J-P Suomela, R. Tahvonen, J. Vaarno, M. Venojarvi, J. Viikari, H. Kallio