Blueberries and Strawberries Help the Older Brain

Once again the Nurses’ Health Study has yielded an interesting association – this time, in an industry-sponsored analysis, Harvard researchers have looked for a link between eating high-flavonoid foods and changes in cognitive decline.  Their findings are published in the Annals of Neurology.

Starting in 1980, female nurses in the study completed a food frequency questionnaire every 4 years.  Between 1995 and 2001 participants reaching the age of 70 were administered 6 different cognitive tests, every two years.  The rate of cognitive decline was calculated over a 4-year period.

There were more than 16,000 women aged 30 to 55 at enrollment.  Over the 4 years' testing, higher intake of blueberries and strawberries was linked to lower rates of cognitive decline. The effect was most marked in women who ate at least one serving of blueberries or two servings of strawberries per week.  The differences in decline rates showed that berry-eating was associated with a delay of cognitive decline of up to 2½ years.  Similar but less strong links were seen with nutritional components of these berries – total flavonoids, in particular anthrocyanidins.       

The researchers warn that they can’t rule out the possibility that the preserved cognition in those eating more berries might have also been influenced by other lifestyle choices, such as exercising more;  in other words, they’ve demonstrated an association, not a cause-and-effect.  However, increasing berry intake is a fairly simple dietary modification, and probably worth doing if you enjoy eating fruit.

Your Commute and Where You Live Can Affect Your Health

Think carefully when you decide to buy a home; its location can affect your health, as two reports show.  A long commute to work may be hazardous to your health, according to a study reported in the American Journal of Preventive Medicine.  Washington University, St Louis, researchers gathered data from 4,200+ people living in 12 Texas metropolitan counties.  They measured the subjects’ commuting distance using an appropriate road network map.  In addition, numerous health factors were determined – self-reported physical activity, cardiorespiratory fitness, a variety of cardiovascular risk factors, smoking, alcohol use, and family history of diseases.   

The results of analyses showed that longer commuting distance were associated with lower physical activity and cardiorespiratory fitness, and increased body mass index (BMI), waist circumference, and blood pressure readings.  After adjustments to account for the effects of lessened physical activity and cardiorespiratory fitness, commuting distance remained associated with BMI, waist circumference, and diastolic blood pressure. 

Another factor in cardiovascular health may be living near a major roadway.  Boston researchers have examined the relationship between residential proximity to a major roadway and 10-year survival after a heart attack (myocardial infarction or MI).  Their findings are published in the journal Circulation. They studied data from 3,800+ people hospitalized for an acute MI from 64 centers across the USA, from 1989 to 1996.  Subject with an institutional address or only post office box addresses were excluded, leaving 3,547 subjects for analysis. 

During 10 years of follow-up, 1,071 participants died – mostly from a cardiovascular cause. After adjustments for individual lifestyle, social, and environmental factors, analysis showed that the risk of death from any cause was greater for those living nearer to a major road.  Those who lived within 100 meters (110 yards) of a major road were more likely to die within 10 years than those living more than 1,000 meters (0.6 miles) away.  Further studies are clearly needed: air pollution, noise, and other factors may be responsible for the association.

Zinc and the Common Cold - Redux

Over a year ago I posted a piece about the use of oral zinc in treating symptoms of the common cold.  This over-the-counter remedy has become increasingly popular.  Now Canadian researchers have done a meta-analysis of published clinical studies, to better define the effectiveness and side effects of oral zinc formulations in treating cold symptoms.  Their results are published in the Canadian Medical Association Journal.

The analysis covered all randomized controlled trials comparing orally administered zinc with placebo or no treatment.  A total of 17 such studies, with 2,121 participants aged between 1 and 65 years, were included.  Formulations used were zinc gluconate lozenges or tablets, zinc acetate lozenges, zinc sulphate syrup, zinc gluconate, and zinc acetate.  Attention was focused on the duration of symptoms. 

Overall, zinc shortened the duration of symptoms by an average of 1.65 days.  Most importantly, however, the shortening of symptoms was negligible in children (up to age 18), compared to 2.63 days in adults.  Higher doses – more than 75 mg – produced a shortening of 2.75 days vs. 0.84 days with less than 75 mg doses.  The severity of symptoms at day 3 of the cold was similar in zinc patients and placebo patients. 

Adverse events were 24% more common with zinc medication; the most common were bad taste (65% more frequent) and nausea (64% more frequent).

The 17 studies showed a wide variation in their experimental designs, and were by no means well-suited to combination for analysis.  The authors of the report state that: Although oral zinc treatment may attenuate the symptoms of the common cold, large high-quality trials enrolling adults and children are needed.  Until further evidence becomes available, there is only a weak rationale for physicians to recommend zinc for the treatment of the common cold.”  It’s unlikely that such studies will be completed in the next few years, so I suggest, in the meantime, adults may try a zinc preparation for themselves, and see if the good effects outweigh the likely side effects.

Sodas and Stroke Risk

The Nurses’ Health Study and the Health Professionals Follow-Up Study have already proved to be mines of health information.  Analyses of different factors of lifestyle and environment have provided numerous associations that can form hypotheses about causes of diseases.  The most recent example comes from a search for relationships between beverage consumption and cardiovascular disease.  It’s an analysis done by scientists at the Cleveland Clinic and published in the American Journal of Clinical Nutrition.

The Nurses’ Health Study provided 28-year data from 84,000 women and the Health Professionals Study 22 years’ data from 43,300 men.  A total of 4,354 strokes (mostly ischemic) allowed relative risks of stroke to be calculated in persons who drank sugar-sweetened soda, low-calorie (“diet”) soda, caffeinated coffee, and decaffeinated coffee.

The risk of a stroke for those taking one or more servings of sugar-sweetened soda per day was 16% higher in the soda-drinkers (i.e. a Relative Risk, or RR, of 1.16).  And for those drinking 1 or more servings of diet soda per day it was also 16% higher.  When adjustments were made for the possible influence of diabetes and high blood pressure, the results were slightly weaker but still present.

In a second analysis, the researchers found that one serving of caffeinated coffee was associated with a 10% lower risk of stroke than that of one serving of sweetened soda.  And a daily decaffeinated coffee serving had a 9% lower risk than a sugar-sweetened soda.  Similar reductions in risk were seen when the comparison was against low-calorie soda.

Although this is a study showing an association, and not causality, it should help discourage consumption of sodas (sweetened or “diet”), at least until confirmation or refutation is available from controlled prospective studies.  If you must drink sodas – rather than tap water – take a cup of coffee, too.

A Noninvasive Paternity Test in Pregnancy from 8 Weeks Onward

In some situations, a pregnant woman needs to be able to determine the paternity of her unborn child early in the pregnancy.  To date, the only reliable means have been invasive tests, like amniocentesis and sampling the chorionic villi.  These tests may be done from the 15^th to the 22^nd week, but they (rarely) increase the risk of miscarriage or minor abnormalities in the baby.  Now a simpler method has been reported in a letter to the New England Journal of Medicine.  It only requires a blood sample from the mother, taken from the 8^th week onwards.  The method picks out cell-free fetal DNA and allows comparison between the male-derived components and samples from the adult “males of interest”, or putative fathers.

The investigators tested their method on blood samples from 30 women who were 8-14 weeks into their pregnancy.  Each sample was paired with blood from the biologic father and then randomly grouped with one of 29 samples from unrelated men.  In all cases the test identified the biologic father and rejected DNA from the unrelated male – a highly statistically significant result.       

This is a significant step forward in, for instance, alleged rape investigations.  As many as 78% of terminations of unintended pregnancies are done before 10 weeks, it’s likely that more paternity cases would be resolvable by the use of this test.

Do You Grind Your Teeth at Night?

Bruxism is the term used to describe excessive teeth-grinding.  It’s probably stress-related, and it can be severe enough to cause a whole range of symptoms and health problems – see the link. At night, the grinding can be noisy enough to bother sleeping partners.  Now two reports given at the American Academy of Neurology meeting provide hope for relief from an unexpected direction – Botox injections.  (I’ve been collecting new indications for Botox since it was discovered, and this one is the latest addition to the list). 

The first study, from the University of Texas, was a double-blind, placebo-injection controlled trial of onabotulinum-A in subjects with nocturnal bruxism.  Patients underwent a test night in the sleep lab, where 6 were excluded from the study as they failed to show bruxism on the polysonograph.  Twenty-three were randomized to either Botox or placebo injections.

Scores on scales for bruxism symptoms and pain at week 4 both showed significant improvement with Botox relative to placebo: averages 47.3 & 44.2 for placebo, 64.5 & 65.0 for Botox, respectively. Non-significant trends in favor of Botox were found for headache, sleep quality and anxiety.  Two of 13 Botox subjects complained of a change in their smiles.  Bruxism symptoms in the Botox group were improved for an average of 103 days with Botox vs. 38 days with placebo. 

The second study, which reported on just 4 patients, came from the Henry Ford Health System in Detroit.  The subjects had developed bruxism after an oxygen-depriving brain injury.  All 4 received Botox intramuscularly (into the jaw muscles); two of them received multiple injections separated by 2 weeks to 3 months.  All 4 of them “responded positively” to the injections, with no side effects reported.

So, this leads the way for more well-controlled clinical studies in this interesting (and annoying) condition, so that FDA can be convinced to add the indication to the growing list of Botox uses.

Don’t Skip Breakfast . . .

. . . if you want to lower your risk of developing type 2 diabetes.   That’s the message delivered by a study reported in the American Journal of Clinical Nutrition.  Scientists at the Harvard School of Public Health examined the possible associations between skipping breakfast, snacking, and the risk of type 2 diabetes in men.

They followed 29,000 men for 16 years as part of the Health Professionals Follow-Up Study; they were free of diabetes, cardiovascular disease, and cancer at baseline, when their eating patterns were assessed.

There were 1,944 cases of type 2 diabetes documented during the follow-up period.  After adjusting for known risk factors for diabetes, including body mass index (BMI), analysis showed that the men who skipped breakfast were 21% more likely to develop diabetes than those who didn’t. Another analysis showed that men who ate only once or twice a day were 25% more likely to develop diabetes than those who had 3 meals a day.  These findings were unaffected by differences in BMI or in the diet quality.  Snacking between regular 3-meals-a-day meals was not helpful, however; this behavior was linked to increased BMI levels, and also to an increased risk of diabetes.

The exact mechanism by which breakfast exerts its ‘protective’ effect must await further studies.  However, it’s pretty clear that you shouldn’t skip breakfast in any attempt to limit calories – cut out the snacks instead.

Supplements Carry Their Own Risks!

Nutritional health supplements are used by about half the US population, although proof of their clinical effectiveness is usually lacking.  Some supplements are marketed as protection against cancer, but there’s no evidence that they work from controlled clinical trials.  Now there’s a report that high doses of some supplements can actually increase the risk of cancer.  It’s published in the Journal of the National Cancer Institute.

University of California San Diego Cancer Center UCSD-CC) researchers reviewed available medical literature for supplements that were tested in adequate clinical studies or in large well-designed observational studies.  They found some lab studies that supported the use of antioxidants (e.g. beta-carotene, alpha-tocopherol, and vitamn C), folic acid, vitamin D, and calcium to prevent cancer in animals or cell-culture models. But 7 well-designed and well-conducted clinical studies failed to support the favorable laboratory evidence in the case of beta-carotene, alpha-tocopherol, selenium, and vitamins A, C, and E, alone or in combination.  One exception – a trial in China showed a 13% reduction in cancer mortality and a 21% reduction in gastric cancer mortality in people randomized to a combination of beta-carotene, vitamin E, and selenium.

Several antioxidant trials have shown increased cancer risk with supplementation, the UCSD-CC investigators wrote.  Most notably, two randomized trials of patients at high risk for lung cancer because of smoking or exposure to asbestos showed an increased incidence of lung cancer in the subjects taking beta-carotene.  And two randomized clinical studies showed an increased risk of prostate cancer and precancerous colon lesions (adenomas) in subjects taking long-term folic acid long-term.  With regard to vitamin D, the authors stated: “there was not enough evidence to state that there is a causal association between low vitamin D intake and increased cancer risk."  More studies are clearly needed to determine whether vitamin D has any preventive effects on cancer. 

Conclusions?  The researchers write:  "Given the current state of the evidence, do we need to conduct more randomized controlled trials of dietary supplements to assess their efficacy for cancer prevention?  We do, but these trials must be designed strategically and in light of lessons learned from previous studies.  In the absence of convincing evidence that more will be better, we probably do not need more trials in nutrient-replete populations”.  In other words, there may not be any evidence of the benefits of supplements in preventing cancer.  I say, save your money!