Monday, September 30, 2013

Walnuts in Diet Can Improve Endothelial Functions for Overweight Adults

Crazy for snacks, go nuts, walnuts to be exact.

Medical researchers from the Yale-Griffin Prevention Research Center in Connecticut have found evidence suggestive that adding walnuts to one's diet can protect against diabetes and heart disease in at-risk individuals.

The research found that daily intake of 56g* of walnuts improves endothelial function in overweight adults with visceral adiposity. The addition of walnuts to the diet does not lead to weight gain.

Walnuts are a uniquely rich source of a-linolenic acid (ALA), and epidemiological studies suggest that plant-derived ALA may confer particular cardiovascular benefits. A meta-analysis investigating the impact of walnut consumption on blood lipids showed that walnut-enriched diets significantly decreased total cholesterol and low-density lipoprotein cholesterol (LDL-C) when compared with control diets for the duration of the short-term trials. Furthermore, walnuts are also rich in tocopherol, phenolic antioxidants, folic acid, and magnesium, nutrients that have been shown to impact endothelial function favourably.

For the study, a sample of 46 adults aged 30-75 were selected. Participants had a Body Mass Index larger than 25, and a waist circumference exceeding 40 inches for men and 35 inches for women. They were also required to be non-smokers, and all exhibited one or more additional risk factors for metabolic syndrome, a precursor of diabetes and cardiovascular disease. The group was randomly assigned to two 8-week sequences of either a walnut-enriched ad libitum diet or an ad libitum diet without walnuts. Those chosen for the walnut diet were instructed to consume 56g of shelled, unroasted English walnuts per day as a snack or with a meal.

FMD or flow-mediated vasodilatation of the brachial artery improved significantly from baseline in subjects on the walnut-enriched diet as compared with the control diet. Beneficial trends in systolic blood pressure reduction were seen, and maintenance of the baseline anthropometric values was also observed. Secondary measures included serum lipid panel, fasting glucose and insulin, were unaltered.

"We know that improving diets tends to be hard, but adding a single food is easy," explained Dr. David Katz, Director of the Yale-Griffin Prevention Research Center and lead author of the research team. "Our theory is that if a highly nutritious, satiating food like walnuts is added to the diet, there are dual benefits: the benefits of that nutrient rich addition and removal of the less nutritious foods."


The above story is based on materials provided by Taylor & Francis, via AlphaGalileo.

The original research article is now available online in the Journal of the American College of Nutrition:

Katz DL, Davidhi A, Ma Y, Kavak Y, Bifulco L, Njike VY. Effects of walnuts on endothelial function in overweight adults with visceral obesity: a randomized, controlled, crossover trial. J Am Coll Nutr. 2012 Dec;31(6):415-23. 

Click HERE to read the full text.

* AUD1.30 (RM3.90) for 56g of Walnuts at Coles

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Friday, September 27, 2013

Negative Emotions in Response to Daily Stress Take a Toll On Long-Term Mental Health

Our emotional responses to the stresses of daily life may predict our long-term mental health.

Psychological scientist Susan Charles of the University of California, Irvine and colleagues conducted a study to answer a long-standing question: 

Do daily emotional experiences add up to make the straw that breaks the camel's back, or do these experiences make us stronger and provide an inoculation against later distress?

Using data from two national surveys, the researchers examined the relationship between daily negative emotions and mental health outcomes ten years later.

Participants' overall levels of negative emotions predicted psychological distress (e.g., feeling worthless, hopeless, nervous, and/or restless) and diagnosis of an emotional disorder like anxiety or depression a full decade after the emotions were initially measured.

Participants' negative emotional responses to daily stressors -- such as argument or a problem at work or home -- predicted psychological distress and self-reported emotional disorder ten years later.

The researchers argue that a key strength of the study was their ability to tap a large, national community sample of participants who spanned a wide age range. The results were based on data from 711 participants, both men and women, who ranged in age from 25 to 74. They were all participants in two national, longitudinal survey studies: Midlife Development in the United States (MIDUS) and National Study of Daily Experiences (NSDE).

According to Charles and her colleagues, these findings show that mental health outcomes aren't only affected by major life events -- they also bear the impact of seemingly minor emotional experiences. 

The study suggests that chronic nature of these negative emotions in response to daily stressors can take a toll on long-term mental health.


The above story is based on the April 2, 2013 news release by Association for Psychological Science.

This study has been published in Psychological Science, a journal of the Association for Psychological Science:
Charles ST, Piazza JR, Mogle J, Sliwinski MJ, Almeida DM. The Wear and Tear of Daily Stressors on Mental Health. Psychological Science, 2013; DOI: 10.1177/0956797612462222

Thursday, September 26, 2013

Red Grapes, Blueberries May Enhance Immune Function

My sister, Soo Inn's blueberries

Compounds in these fruits work alongside vitamin D and specific gene, lab study found.

In an analysis of 446 compounds for their the ability to boost the innate immune system in humans, researchers in the Linus Pauling Institute at Oregon State University discovered just two that stood out from the crowd -- the resveratrol found in red grapes and a compound called pterostilbene from blueberries.

Both of these compounds, which are called stilbenoids, promote health because they work in synergy with vitamin D to increase expression of the CAMP gene, known to play a role in the functioning of the body's immune system.

Resveratrol has been the subject of studies for a range of possible benefits, from improving cardiovascular health to fighting cancer and reducing inflammation. This research is the first to show a clear synergy with vitamin D that increased CAMP expression by several times, scientists said.

The CAMP gene itself is also the subject of much study, as it has been shown to play a key role in the "innate" immune system, or the body's first line of defense and ability to combat bacterial infection. The innate immune response is especially important as many antibiotics increasingly lose their effectiveness.

A strong link has been established between adequate vitamin D levels and the function of the CAMP gene, and the new research suggests that certain other compounds may play a role as well.

Stilbenoids are compounds produced by plants to fight infections, and in human biology appear to affect some of the signaling pathways that allow vitamin D to do its job, researchers said. It appears that combining these compounds with vitamin D has considerably more biological impact than any of them would separately.

Because the study was only conducted in a lab setting and not in humans, more research is needed before saying that consuming the compounds from fruits in diet would have immune-boosting effects. But still, the idea that certain foods could potentially improve the immune system is intriguing, researchers said.


The above story is based on the September 17, 2013 news release by Oregon State University.

The study has been published in the journal Molecular Nutrition and Food Research:

Guo C, Sinnott B, Niu B, Lowry MB, Fantacone ML, Gombart AF. Synergistic induction of human cathelicidin antimicrobial peptide gene expression by vitamin D and stilbenoids. Mol Nutr Food Res. 2013 Sep 14. doi: 10.1002/mnfr.201300266


See also our September 1, 2013 report: Whole Fruits Linked to Lower Risk of Type 2 Diabetes

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