You may be pleased to hear that some of your favourite foods contain flavanols. Essentially, flavanols are a type of super antioxident that reduces the risk of numerous conditions, such as stroke, heart disease and cancer. Foods containing flavanols include purple grapes, red wine, tea and cocoa. In its purest form, chocolate is one of the richest sources of flavanols and antioxidants. Unfortunately, the chocolate you usually buy from the sweet shop has had most of the flavanols removed because they can have a bitter taste. According to Norman Hollenberg, Professor of Radiology at Harvard Medical School, a flavanol called epicatechin is important enough to class as a vitamin. It is commonly found in cocoa, tea and wine.1
Research has shown that flavanols increase blood flow to the brain and reduce blood pressure. According to Harold Schmitz, PhD, Chief Science Officer at Mars,
‘Though more research is needed, these findings raise the possibility that flavanol-rich cocoa products could be developed to help slow brain decline in older age…’2
In 1997, a ground-breaking study found that the island-dwelling Kuna Indians of Panama were 1,280 percent less likely to die of heart disease than people on the mainland and 630 percent less likely to die of cancer. Hollenberg showed that their blood pressure did not rise as they grew older and there was hardly any incidence of hypertension. He concluded that these benefits came from the high flavanol cocoa they drank in large quantities. According to Hollenberg,
‘If these observations predict the future, then we can say without blushing that they are among the most important observations in the history of medicine … We all agree that penicillin and anaesthesia are enormously important. But epicatechin could potentially get rid of 4 of the 5 most common diseases in the western world, how important does that make epicatechin? I would say very important.’3
Possible benefits of Flavanols for stroke
After a stroke, there is a reduction of blood flow to damaged areas of the brain. Consequently, brain cells may remain dormant or die. This causes debilitating effects, such as paralysis and aphasia. By eating foods or supplements rich in flavanols, it may be possible to increase blood flow within the brain. In 2008, a trial conducted by Harvard scientists tested a group of healthy adults aged 59 to 83. After one week, they found that those who regularly drank flavanol-rich cocoa had, on average, an eight percent increase in blood flow to the brain. After two weeks, brain blood flow had increased by an average of 10 percent. They reported:
‘Our data suggest a promising role for regular cocoa flavanol’s consumption in the treatment of cerebrovascular ischemic syndromes, including dementias and stroke.’4
Soya beans and chickpeas are also rich in flavanols, particularly isoflavones, which have a similar effect to the statin-based drugs used to fight cholesterol. Researchers at the University of Hong Kong have shown that isoflavones help to promote blood flow through the arteries. They tested 102 stroke survivors over 12 weeks. Half the participants received 80 mg of isoflavones a day; the other half received a dummy pill (placebo). At the end of the trial, the group that received isoflavones had ‘improved significantly’. The team recommends further research.5
Arguments against using Flavanols for stroke
There has been a great deal of research on cocoa flavanols. Some of the most impressive results have come from chocolate makers Mars, who have been supporting this research for more than 15 years. Some people might speculate that the company has a vested interest because it launched a high-flavanol range of products called CocoaVia™. However, this range of bars and drinks was ‘part of a limited market test’ and was withdrawn in 2009.6
Another problem is that conflicting reports exist regarding the protective effects of dietary flavonoid intake. According to the Linus Pauling Institute at Oregon State University,
‘Of seven prospective cohort studies that examined relationships between dietary flavonoid intake and the risk of stroke, only two studies found that higher flavonoid intakes were associated with significant reductions in the risk of stroke while five found no relationship.’7
High-flavanol cocoa products must not be confused with commercial chocolate bars and drinks. Most commercial chocolate has been stripped of its flavanol content and the makers have added fat and sugar8.
1. This article outlines some of the research and benefits of cocoa flavanols. 'Cocoa flavanols may boost blood flow in the brain’ by Stephen Daniells, 19 Aug. 2008. Source: Neuropsychiatric Disease and Treatment. Volume 4, pp 433-440.
2. This article outlines some of the research and benefits of cocoa flavanols. 'Cocoa shows cardiovascular health benefits in study' (reporting by Mark Landas). Scientist Live.
Notes and references
- ‘Cocoa, Flavanols and Cardiovascular Risk’ by Norman K. Hollenberg; Harold Schmitz; Ian Macdonald; Neil Poulter. Boston Globe, 11/29/2004
- ‘Hypertension, the Kuna, and the Epidemiology of Flavanols’ by McCullough, Marjorie L.; Chevaux, Kati; Jackson, Lilian; Preston, Mack; Martinez, Gregorio; Schmitz, Harold H.; Coletti, Caroline; Campos, Hannia; Hollenberg, Norman K. In Journal of Cardiovascular Pharmacology. 47:S103-S109, June 2006.
- Quoted in 'Cocoa 'Vitamin' Health Benefits Could Outshine Penicillin'. In ScienceDaily, Mar. 12, 2007
- 'Cerebral blood flow response to flavanol-rich cocoa in healthy elderly humans' by Farzaneh A Sorond, Lewis A Lipsitz, Norman K Hollenberg, Naomi DL Fisher. In Neuropsychiatric Disease and Treatment, April 2008, Volume 2008:4(2) Pages 433-440. The research in this paper was supported in part with a research grant from Mars, Incorporated.
- ‘Reduction of C-Reactive protein with isoflavone supplement reverses endothelial dysfunction in patients with ischaemic stroke’ by Chan YH, Lau KK, Yiu KH, Li SW, Chan HT, Fong YT, Tam S, Lau CP & Tse HF. In European Heart Journal 2008; 29: 2800-2807.
- Flavonoids, Micronutrient Information Center, Linus Pauling Institute, Oregon State University
- There are a number of fruit and chocolate products that are advertised as high in flavanols, such as Choxi+ and Acticoa.