Scientists recently reported the first human evidence that blueberries can boost memory and might even help to ward off dementia. Nine older-age adults with early memory decline were asked to drink around two cups of a commercially available blueberry juice every day for two months, while a control group drank a beverage without blueberry juice. Tests taken before and after revealed that those who drank the blueberry juice showed significant improvements in learning and memory, leading the researchers to conclude that blueberries may offer neurocognitive benefits (J Agric Food Chem, 2010 Jan 4; Epub ahead of print).
These results confirm the findings of previous animal studies, which showed that blueberries can reverse age-related deficits of both brain and behavioural function. Rats fed a blueberry-supplemented diet performed better in maze and object-recognition tests, as well as in tests of balance and coordination.
Similar benefits have been seen with cranberries and strawberries, although it appears that different kinds of fruit may well be affecting different parts of the brain. In one study, both blueberries and strawberries were able to protect rats against radiation-induced mental deficits although, while blueberries improved learning, strawberries boosted memory (J Agric Food Chem, 2008; 56: 636-41).
Numerous studies have suggested that berries are potent cancer-fighters. In one test-tube study, extracts of six different kinds of berries-blueberry, blackberry, black raspberry, red raspberry, cranberry and strawberry-inhibited the growth of human mouth, breast, colon and prostate cancer cells. In addition, two of the extracts-black raspberry and strawberry-were able to stimulate apoptosis (cell death) in colon cancer cells (J Agric Food Chem, 2006; 54: 9329-39).
The now popular aca'i and goji berries also have anticancer potential. Aca'i berries appear to be effective against leukaemia cells, while the polysaccharides found in goji berries kill prostate cancer cells (J Agric Food Chem, 2006; 54: 1222-9; J Med Food, 2009; 12: 695-703).
However, to determine whether or not these lab results apply to real life, human trials are currently ongoing.
Berries may also have a role to play in the prevention of heart disease. A group of 72 middle-aged men and women were asked to consume either two portions of berries daily (100 g of berries plus a small glass of a berry drink) or control products, for two months. The berry group-which included bilberries, lingonberries, blackcurrants, strawberries, chokeberries, and rasp-berries-ate an assortment of the berries whole, pureed or in juice form.
At the end of the study, the berry-eaters saw systolic blood pressure reductions of up to 7.3 mmHg, while levels of HDL ('good') cholesterol rose by over 5 per cent. The researchers also noted favourable changes in platelet function (blood cells involved in clotting) in those who ate berries (Am J Clin Nutr, 2008; 87: 323-31).
Several animal studies suggest that some berries may have antidiabetic effects. Indeed, a recent study in mice concluded that bilberries can improve hyperglycaemia and insulin sensitivity in type 2 diabetes (J Nutr, 2010; 140: 527-33).
Although human trials are scarce, one found that a dietary supplement containing blueberry and sea buckthorn (seaberry; genus Hippophae) concentrates was beneficial in the treatment of type 1 diabetic children (Acta Physiol Hung, 2008; 95: 383-93).
Berries appear to be promising in the prevention of bowel disease (www.berryhealth.org/abstracts/ReedAbstract.html), urinary tract infections (Scand J Urol Nephrol, 2009; 43: 369-72) and eye disorders such as cataracts and macular degeneration (Adv Gerontol, 2005; 16: 76-9).
It's likely that, with further research, there will be many more reasons to make sure that these colourful fruit are part of your daily diet.
WDDTY VOL 21 NO 1