Thursday, December 4, 2008

Eating Fish Thwarts Brain Damage - Reuters Health


NEW YORK—Older adults who regularly eat fish may have a lower risk of subtle brain damage that contributes to stroke and dementia—as long as the fish isn’t fried—researchers reported recently.

In a study that followed 3,660 adults age 65 and older, Finnish researchers found that those who ate more fish were less likely to show certain “silent” brain infarcts—tiny areas of tissue that have died because of an insufficient blood supply—on an MRI scan.

The tissue damage is considered silent, or “subclinical” because it causes no obvious symptoms and can only be detected through brain scans. It can, however, raise a person’s longer-term risk of having a stroke or developing dementia.

Among older adults in the current study, those who said they ate tuna and other baked or broiled fish at least three times per week were one-quarter less likely than those who rarely ate fish to have subclinical brain infarcts at the study’s start.

Fish eaters also tended to be less likely to develop new infarcts over the next five years.

No such benefits were linked to consumption of fried fish, however, the researchers report in the journal Neurology.

While the study cannot conclusively point to the reason for the brain benefits, it’s likely that omega-3 fatty acids—healthy fats found mainly in oily fish—play a key role, according to Dr. Jyrki K. Virtanen and colleagues at the University of Kuopio.

When the researchers estimated study participants’ intake of two major omega-3 fatty acids—EPA and DHA—they found a link between higher intake and lower risk of silent brain infarcts.

In addition, the researchers note, the lack of a protective effect from fried fish may stem from the fact that foods like fish burgers and fish sticks are typically made from fish low in omega-3.

Overall, the findings add to evidence that fish rich in omega-3 fats—like salmon, mackerel and albacore tuna—may have “important health benefits,” the researchers write.

“Previous findings have shown that fish and fish oil can help prevent stroke, but this is one of the only studies that looks at fish’s effect on silent brain infarcts in healthy, older people,” Virtanen said in a written statement.

“More research is needed as to why these types of fish may have protective effects, but the omega-3 fatty acids EPA and DHA would seem to have a major role.” Virtanen added.

Silent brain infarcts can raise a person’s risk of both stroke and cognitive decline. It’s estimated that about 20 percent of adults age 65 and up who are free of silent infarcts will develop at least one within five years.

The American Heart Association recommends that all adults strive to eat at least two fish meals per week, preferably fatty fish, for the sake of their cardiovascular health.

Source: Neurology, August 5, 2008

Last Updated
Aug 17, 2008

Tuesday, December 2, 2008

Garlic Can Reduce Blood Pressure By Dr. John Briffa


Garlic is an oft-touted natural remedy, particularly regarding affairs of the heart. Regular garlic consumption has been said to improve cardiovascular health. In the past, one way it was believed to improve health was its ability to reduce blood pressure.

A previous review found seven trials in which the effects of garlic (powder) were compared with placebo: Three showed a significant reduction in systolic blood pressure (the higher blood pressure value), while four showed a significant reduction in diastolic blood pressure (the lower blood pressure value). Overall, the results indicated that garlic had genuine blood-pressure-lowering potential [1].

Since this review was published, other evidence has come to light. Recently, scientists brought the state of the science on this topic up to date with a meta-analysis, which combined the results of eleven relevant studies [2].

The results demonstrated the following: overall, a statistically significant reduction in systolic blood pressure (an average reduction of 4.6) and overall, no statistically significant reduction in diastolic blood pressure. [Blood pressure is measured in mmHg.]

The authors of this study also went on to separate out the data from individuals in studies who were deemed to have high blood pressure (blood pressure of 140/90 or higher).

In this group, the results showed a statistically significant reduction in systolic blood pressure (an average reduction of 8.4) and a statistically significant reduction in diastolic blood pressure (an average reduction of 7.3).

The authors point out that if the overall effect of garlic on blood pressure seen in the review was applied to the population as a whole, risk of cardiovascular disease and death from cardiovascular disease would be expected to fall by 8 percent to 20 percent. Perhaps it should be borne in mind that garlic might possibly reduce the risk of cardiovascular disease by other mechanisms as well, notably an anti-coagulant effect (garlic is a blood-thinner, like aspirin).

The dosages of garlic used in the studies on blood pressure were 600 mg to 900 mg. One of garlic’s main active ingredients is believed to be allicin. The dosages used in the studies would translate to a daily allicin dose of 3.6 mg to 5.4 mg. One single fresh clove of garlic contains 5 mg to 9 mg of allicin. For maximum effect, the garlic should be raw (uncooked).

References:

[1.] Silagy CA, et al. A meta-analysis of the effect of garlic on blood pressure.
Journal of Hypertension. 1994 Apr; 12(4): 463–8.

[2.] Ried K, et al. Effect of garlic on blood pressure: A systematic review and meta-analysis. BMC Cardiovascular Disorders 2008, 8:13 [Epub 16th June]

Dr. John Briffa is a London-based doctor and author with an interest in nutrition and natural medicine. Dr. Briffa's Web site

Last Updated
Oct 23, 2008