Friday, December 31, 2010

Dark Chocolate May Promote Gut Health

Want to help ensure that the good bugs outnumber the bad in your belly?
 
New findings suggest it makes sense to cozy up with some cocoa, or enjoy a bit of extra dark chocolate.
 
In a preliminary clinical trial, people who drank a beverage rich in cocoa-derived antioxidants enjoyed a significant increase in their gut levels of beneficial bacteria.
 
Better yet, this increase was accompanied by reductions in a microbe associated with diarrhea and constipation (clostridia), and in blood levels of cholesterol, triglycerides, and C-reactive protein (CRP) … a marker of inflammation linked to heart risks.
 
The study, which was conducted by researchers from the UK’s Reading University and chocolate giant Mars, Inc., is the first to demonstrate that cocoa flavanols can boost the numbers of beneficial bacteria in people’s guts.
 
Do flavanols act as antioxidants, gene-tweakers ... or both?
Most research into the potential cardiovascular benefits of cocoa and dark chocolate relates to presumed antioxidant effects of the flavanol-type polyphenols that abound in both.
 
And recent evidence reviews agree there's ample preliminary evidence that cocoa flavanols support vascular health in several ways (Corti R et al. 2009; Mulvihill EE et al. 2010; Ostertag LM et al. 2010; Rimbach G et al. 2009).
 
The flavanols in cocoa, tea, and berries are commonly referred to as “antioxidants”, because they display potent free-radical-squelching effects in test-tube experiments.
 
However, like other polyphenol compounds in plant foods, it’s increasingly apparent that flavanols exert their beneficial effects through “nutrigenomic” influences on gene switches in our cells … rather than through direct, substantial antioxidant effects in the body (Scheid L et al. 2010)
 
The most promising cocoa flavanols are procyanidins – which are also found in berries and grapes – and catechins (flavan-3-ols), which occur in green tea.
Before we delve into the details, let’s review the research on the role of intestinal microbe colonies in human health.
 
Probiotics and prebiotics: A quick primer
People’s gastrointestinal tracts play host to many millions of microbes, most of which are either neutral or beneficial.
 
Some, such as lactobacilli and bifidobacteria, seem virtually essential to immunity and overall health.
 
A healthy gut ecosystem is one in which beneficial micro-organisms greatly outnumber potentially harmful bugs. The opposite, unhealthful balance is referred to as “dysbiosis”.
 
The most critical microbial colonies occur in the colon, where, as the authors of a recent evidence review wrote, “… a true symbiosis [between probiotic microbes and] the host [person] exists that is a key for well-being and health.” (Roberfroid M et al. 2010)
 
Thanks to many human studies, it’s clear that certain foods or food factors can change the microbial composition of the gut in significant, beneficial ways.
 
“Probiotic” foods such as yogurt and fermented vegetables with active cultures contain the same beneficial microbes found in the human gut – mostly lactobacilli and bifidobacteria – and eating these cultured foods appears to support immune health by keeping gut-based pathogens in check.
 
(Doctors often prescribe lactobacilli supplements to patients taking antibiotic drugs, which kill these beneficial bacteria along with pathogenic microbes.)
 
In contrast, “prebiotic” food factors bring intestinal benefits indirectly, by serving as food for lactobacilli and other beneficial bacteria.
 
Prebiotics are defined as “non-digestible (by the host) food ingredients that have a beneficial effect through their selective metabolism in the intestinal tract.” (Gibson GR et al. 2004).
 
As the authors of the same evidence review put it, “… the prebiotic effect [of certain food factors] is now a well-established scientific fact.” (Roberfroid M et al. 2010)
 
The chief prebiotic supplements are three plant fibers called inulin, galactooligosaccharides (GOS), and fructooligosaccharides (FOS), which are found in or derived from Jerusalem artichoke root, chicory root, burdock root, and beets.
 
Clinical study detects prebiotic potential from cocoa compound
Last year, the authors of a Nestle-funded human study reported that daily consumption of 40 grams (1.4 ounces) of dark chocolate lowered levels of stress-related hormones (cortisol) and neurotransmitters in participants diagnosed with anxiety.
 
Those changes were linked to changes the composition of their microbial gut colonies.
 
As they described the implications of their findings, “… subtle changes in dietary habits, such as eating dark chocolate, can benefit both host and microflora metabolism with potential long term health benefits”. (Rezzi S 2010).
 
Now, findings from the UK-Mars study suggest that cocoa flavanols may rival the prebiotic effects produced by fructooligosaccharides (FOS), which serve as popular prebiotic supplements.
 
The small but rigorously designed new study was a randomized, double-blind, crossover, controlled clinical trial, led by the University of Reading’s Jeremy Spencer, Ph.D., and sponsored by Mars, Inc. (Tzounis X et al. 2010)
 
For the trial, 21 healthy adults were divided into two groups, with each group assigned to consume a different flavanol-supplemented beverage daily:
Low-flavanol beverage providing 23mg of cocoa flavanols
High-flavanol beverage providing 494mg of cocoa flavanols
The trial began with both groups drinking their assigned beverage daily for four weeks, followed by a four-week “wash-out” period during which they drank neither flavanol-supplemented beverage.
 
The two groups then switched beverages for a further four weeks of daily consumption.
 
Compared with the low-flavanol drink, participants showed significant increases in their gut levels of beneficial bifidobacteria and lactobacilli when they were drinking the high-flavanol beverage.
 
These increases in beneficial microbes were accompanied by reductions in blood levels of cholesterol, triglycerides, and CRP … a marker of inflammation linked to heart health.
 
As the authors wrote, “The increase in the growth of Lactobacillus spp. in response to cocoa flavanols is of note because this bacterial group is associated with beneficial effects in the gut, including an ability to prevent the growth of pathogenic organisms, and most currently accepted prebiotics [e.g., FOS] do not elicit changes [increases] in lactobacilli.” (Tzounis X et al. 2010)
 
The researchers noted that higher gut levels of bifidobacteria are “strongly associated with positive effects in the large intestine, thanks to the ability of bifidobacteria to inhibit the growth of pathogens, drive the synthesis of certain vitamins (e.g., vitamin B-9), and reduce plasma [blood] cholesterol levels.” (Tzounis X et al. 2010)
 
And the researchers noted that, in comparison with two prebiotic food fibers – fructooligosaccharides (FOS) and galactooligosaccharides (GOS) – the cocoa flavanols produced similarly substantial effects at a much lower dose.
 
While encouraging, these findings will need to be repeated in a larger trial and do not justify eating copious amounts of dark chocolate in an attempt to correct medically diagnosed dysbiosis.

Tuesday, December 21, 2010

Passion Flower: A Helpful Botanical for Relaxation

Passion flower (Passiflora incarnata) can be used to combat the effects of stress. The dried above-ground parts of the plant can be found in tincture and extract form - look for standardized whole-plant extracts or capsules containing no less than 0.8 percent flavonoids or isovitexin. Use passion flower for stress reduction, calming without sedation and relief from insomnia (usually combined with other sedative herbs). One dropperful of the tincture in a little warm water, or two capsules of extract, up to four times a day as needed is the adult dosage; children should take half that amount. Use caution if you're also taking MAO-inhibiting antidepressant drugs, and do not take passion flower when pregnant - active compounds may be uterine stimulants.

Eating Blueberries Can Slow Mental Decline

Supplementing the diet with blueberries for one month may slow and even reverse the decline in mental function associated with age, suggest results of a new study with lab rats.

Cognitive performance declines naturally with age, but new results published in Nutrition indicate that one month's supplementation of elderly rats with blueberries was associated with an improvement in the memory scores, as measured in a maze.

In addition, data showed that two months of consuming the bluer-enriched diet was associated with a prolongation of the benefits after the diet was stopped, and the performance of the aging rats was similar to that of younger rats.

“Therefore, 1-, 2-, and 4-months diets substantially reversed the age-related object memory impairment found in 19-month-old rats,” wrote researchers from the University of Houston and Tufts University U.S. Department of Agriculture Human Nutrition Research Center on Aging.

“This illustrates a surprisingly prompt and powerful effect of an antioxidant dietary intervention,” they added.

The berries are booming

Blueberry consumption has previously been linked to reduced risk of Alzheimer’s, and the beneficial effects of the blueberries are thought to be linked to their flavonoid content - in particular anthocyanins and flavanols. The exact way in which flavonoids affect the brain are unknown, but they have previously been shown to cross the blood brain barrier after dietary intake.

It is believed that they may exert their effects on learning and memory by enhancing existing neuronal connections, improving cellular communications and stimulating neuronal regeneration.

Benefits for four legs, benefits for two legs

Earlier this year, researchers from the University of Cincinnati Academic Health Center reported that 12 weeks of consuming a daily drink of about 500 mL of blueberry juice was associated with improved learning and word list recall, as well as a suggestion of reduced depressive symptoms (Journal of Agricultural and Food Chemistry, 2010, Vol. 58, pp 3996–4000).

The study was said to be the first human trial to assess the potential benefits of blueberries on brain function in older adults with increased risk for dementia and Alzheimer’s.

The new study, led by Houston’s David Malin PhD, examined the effects of one or two months of consuming a blueberry-enriched diet in aging Fischer-344 rats.

Results showed that animals receiving the blueberry diet performed better than animals not receiving a berry-enriched diet, and that two months of supplementation resulted in a maintenance of the improved performance after the supplementation period ended. No such effects were observed in the one month group, said the researchers.

“One possible explanation [for this observation] is a ‘threshold hypothesis’,” said the researchers. “This hypothesis assumes there is a threshold concentration of antioxidants, particularly longer-lasting fat-soluble antioxidants, needed to maintain alleviation of memory impairment.

“The 2-month diet might have produced a larger surplus of antioxidant nutrients over the threshold, whereas the 1-month diet might have produced only a scant surplus above the threshold. Then, as the antioxidant nutrients are metabolized, the 1-month diet might soon lose its ability to prevent memory impairment, whereas this loss of effectiveness might hypothetically take much longer after the 2-month diet,” they added.

Furthermore, rats on the blueberry diet increased their memory scores, while the control animals displayed a decline in memory scores.

“The present study is encouraging in terms of potential human application,” wrote Dr Malin and his co-workers. “First, the present results suggest that even a relatively brief blueberry diet might produce measurable benefits. Second, the benefits of several months of the diet might be maintained for a considerable period after the diet is interrupted. Third, blueberry supplementation might possibly reverse some degree of memory impairment that has already developed.

“This raises the possibility that this sort of nutritional intervention might still be beneficial even after certain memory deficiencies have become evident,” they added.

Source: Nutrition
Published online ahead of print, doi: 10.1016/j.nut.2010.05.001
“Short-term blueberry-enriched diet prevents and reverses object recognition memory loss in aging rats “
Authors: D.H. Malin, D.R. Lee, P. Goyarzu, Y-H. Chang, L.J. Ennis, E. Beckett, B. Shukitt-Hale, J.A. Joseph

Monday, December 13, 2010

Omega 3 Oils May Lower Cortisol and Help Reduce Body Fat

Cortisol is a vital hormone that’s key to regulating blood sugar and inflammation … and standing up to acute stresses such as fear, injury, and extreme exertion.
 
Chronically low cortisol levels – a condition known as Addison’s disease – were fatal before this hormone was discovered.
 
But chronically high cortisol levels – which can result from continual stress – is the more common problem, and produces several undesirable outcomes:
Thinning of the skin.
Decreased muscle mass.
Weakened immunity to infections.
Reduced bone formation, increased risk of osteoporosis.
Damage to the brain’s hippocampus and losses to learning and memory.
Chronically high cortisol levels kill brain cells (neurons) … which is the chief reason for the brain shrinkage seen in patients suffering from Alzheimer’s and other forms of senility.
 
A few years ago, UCLA research in patients with mild cognitive impairment found that those who had a smaller-than-average hippocampus were more likely to develop full-blown dementia (Apostolova LG et al. 2006).
 
Cortisol levels rise rapidly in young people placed under stress, but fall back to normal within a few hours after the source of stress is removed. 
 
In contrast, cortisol levels remain high for days in older people, even after the source of stress is gone. 
 
Blood cortisol levels increase with age, and someone aged 65 will have higher average blood levels of cortisol compared with a 25-year-old.
 
Some anti-aging researchers call cortisol the “death hormone”, because it is associated with old age and disease. 
 
Black tea is shown to rapidly normalize cortisol levels after stress, while euphoric experiences – including music, massage, sexual intercourse, and laughing – can lower and stabilize cortisol levels (see “Black Tea May Confer Memory-Saving, Anti-Stress Benefits”).
 
Some studies indicate that fish oils moderate levels of pro-inflammatory cytokines and/or the neurotransmitter norepinephrine, which is a key player in the body’s “flight or fight” response to stress.
 
Five years ago, a small, controlled clinical trial provided the first evidence that fish oil supplements may actually make people feel less stressed (see “Eat Seafood to Ease Stress?”).
 
Fish oil has also been found to improve body composition in preliminary clinical studies … an outcome attributed to various physiological effects of omega-3s.
 
(See “Omega-3s Linked to Healthier Weight and Body Composition”.)
 

 
Now, the outcomes of two small, controlled clinical trials support the hypothesis that omega-3s possess cortisol-lowering and body-fat-reducing powers.
 
Gettysburg trial finds improved body composition and cuts in cortisol
Researchers at Pennsylvania’s Gettysburg College recruited 44 adults for a six-week trial designed to test the effects of safflower oil and fish oil on people’s body composition, metabolic rate, and cortisol levels.
 
The volunteers were divided in two groups, and each took a daily oil supplement:
Safflower oil – four grams, mostly omega-6 fatty acids
Fish oil – four grams, including 2400mg of omega-3 fatty acids (1600mg EPA + 800mg DHA).
 
In tests performed at the end of the six-week study, members of the fish oil group showed significantly lower cortisol levels.
 
In addition, the fish oil group shed body fat and gained lean muscle.
 
There was also a tendency for lower cortisol levels in the fish oil group … as well as a significant correlation between cuts in cortisol and gains in muscle mass … that is, the less cortisol people in the fish oil group had, the more muscle they gained.
 
As the authors wrote, “… [six] weeks of supplementation with FO [fish oil] significantly increased lean mass and decreased fat mass. These changes were significantly correlated with a reduction in salivary cortisol …” (Noreen EE et al. 2010)
 
Interestingly, while the results showed beneficial changes in body composition among the fish oil group, there was no difference in total body weight between the safflower and fish oil groups.
 
Nor were there any rises in resting metabolic rate – which would indicate increased calorie-burning – in either group.
 
Anglo-Iranian team reports that fish oil lowered cortisol
This study comes from the Anglo-Iranian collaboration that found omega-3 EPA equal to the anti-depressant drug fluoxetine (Prozac) among patients diagnosed with major depression … and that combining them provided results superior to either alone (Jazayeri S et al. 2008; see “Omega-3s Affirmed as Mood Lighteners”).
 
For their new study, they analyzed blood taken from the 42 patients who’d participated in the prior eight-week trial of EPA and fluoxetine, both before the trial began and after it ended.
 
The new analysis of the participants’ blood showed that cortisol levels dropped in both the omega-3 EPA group and the group that took both EPA and fluoxetine (Prozac).
 
Some scientists hypothesize that omega-3s might exert anti-depression effects in part by lowering levels of certain pro-inflammatory immune-system proteins (cytokines) associated with depression (IL-1beta and IL-6).
 
But the volunteers showed no changes in their blood levels of either chemical.
 
This led the Iranian team to an intriguing conclusion: “These findings suggest that EPA may exert its therapeutic [anti-depression] effects through reduction of cortisol.”
 
These studies provide good reasons to favor fishy diets … a lighter mood, a healthier body compositions, and healthier aging overall.
 
 

Benefit of Fish Oil for Depression Confirmed

About 21 million American adults suffer from mood disorders, including depression, the world's fourth leading cause of morbidity and death.
 
And a new review of the best clinical evidence strongly supports the conclusions of a prior review, which also found that omega-3 fatty acids from fish oil can enhance treatment of depression.
 
(See “Top Psych Panel Says Omega-3s Deter Depression”.)
 
Our bodies can make the two omega-3s essential to human life and health – EPA and DHA – from the short-chain omega-3 called ALA, which is found in a certain plant foods (leafy greens, walnuts, flax, canola oil).
 
But humans do this very inefficiently, converting only two to 10 percent of dietary ALA into DHA and EPA.
 
Pre-formed EPA and DHA are only found in seafood, with fatty fish having more than lean fish or shellfish. (Omega-3 supplements made from algae only contain DHA.)
 
The authors of a “meta-analysis” of 15 randomized, double-blind, placebo-controlled studies presented their results last week at the annual meeting of the American College of Neuropsychopharmacology.
 
The study – funded by the U.S. National Institutes of Health and conducted by researchers from UCLA and the University of Illinois at Chicago – combined the results of 15 prior clinical trials to arrive at an overall conclusion.
 
The UCLA/UI team, led by John M. Davis, M.D., wrote that their analysis of the evidence showed that “… patients taking omega-3 with either EPA or a combination of EPA and DHA experienced clear antidepressant benefits”. (ACN 2010)
 
However, patients taking only omega-3 DHA showed no anti-depression benefits.
 
As Dr. Davis said, “Our analysis clarifies the precise type of omega-3 fatty acid that is effective for people with depression and explains why previous findings have been contradictory.” (ACN 2010)
 
While omega-3 EPA produces beneficial effects in patients with depression, neither EPA nor DHA appears to improve mood in people who are not depressed.
 
Davis and his team said their analysis suggests that women who consumed few omega-3s were more likely to experience depression during and after pregnancy than women with adequate omega-3s in their diets.
 
“The findings are unambiguous,” said Davis. “Omega-3 fatty acids have antidepressant properties, and this effect is ready to be tested in a large study to establish the dose range and to pave the way for FDA approval.” (ACN 2010)
 
And he made two key points: “In the meantime, omega-3 fatty acids containing EPA could be useful to augment effects of antidepressant medications … [but] patients should always talk with their mental health professional before taking omega-3 fatty acids to alleviate symptoms of depression.” (ACN 2010)