Replacing saturated fat with polyunsaturated fat linked with lower risk of heart disease

People who swap 5% of the calories they consume from saturated fat sources such as red meat and butter with foods containing linoleic acid—the main polyunsaturated fat found in vegetable oil, nuts, and seeds—lowered their risk of coronary heart disease (CHD) events by 9% and their risk of death from CHD by 13%, according to a new study led by Harvard School of Public Health (HSPH) researchers. 

Substitution of 5% of calories from carbohydrate with linoleic acid was associated with similar reductions in risk of heart disease.

"There has been much confusion and sensational headlines about the role of different types of fat in CHD," said Frank Hu, senior author and professor of nutrition and epidemiology at Harvard School of Public Health. "Randomized clinical trials have shown that replacing saturated fat with polyunsaturated fat reduces total and LDL cholesterol. And our comprehensive meta-analysis provides clear evidence to support the benefits of consuming polyunsaturated fat as a replacement for saturated fat."

The study appears in the October 28, 2014 print issue of Circulation.

The researchers performed a systematic review and meta-analysis of prospective cohort studies to summarize the evidence regarding the link between dietary linoleic acid intake and CHD risk in generally healthy people. They identified 13 published and unpublished cohort studies with a total of 310,602 individuals and 12,479 total CHD events including 5,882 CHD deaths.

Results showed that dietary linoleic acid intake is inversely associated with CHD risk in a dose-response manner—meaning, higher intake of linoleic acid resulted in a lower risk of CHD. Comparing the highest to the lowest level of consumption, dietary linoleic acid was associated with a 15% lower risk of CHD events and a 21% lower risk of CHD deaths. These results were independent of common coronary heart disease risk factors such as smoking and other dietary factors such as fiber consumption.

In practice, say the authors, these findings support replacing butter, lard, and fat from red meat with liquid plant oils in cooking and at the table. Although not addressed in this analysis, trans fat from partially hydrogenated vegetable oils should be avoided, they add.

Spices and herbs: Improving health through flavorful eating

Spices and herbs can play a significant role in improving America's health by helping to reduce sodium, calorie and fat intake while making healthy eating more appealing, conclude the authors of a scientific supplement published this month in the peer-reviewed journal Nutrition Today.

The publication, entitled Spices and Herbs: Improving Public Health Through Flavorful Eating, is based on the conference proceedings of a Science Summit convened by the McCormick Science Institute in partnership with the American Society for Nutrition in Washington, D.C., on May 20-21, 2014. The goal of the summit was to bring together academia, health professionals, chefs, government, and the food industry to examine the state of the science on spices and herbs, and to cultivate a dialogue on how flavorful eating can offer potential solutions to improve America's health.

The special edition journal features 16 papers by leading experts that explore the latest research on spices and herbs, including studies that point to the positive impact of spices and herbs on diet quality, as well as other studies that suggest certain spices and herbs may have beneficial effects on satiety, energy metabolism, inflammation, insulin resistance and cardiovascular risk factors.

Until now, little attention has been given to the link between flavor and public health. However, the McCormick Science Institute Summit and these proceedings are helping to create awareness of this important connection.

"We now understand that spices and herbs have a meaningful role to play in bringing flavor to the forefront of today's health and wellness conversations," said Johanna Dwyer, DSc, RD, professor of medicine and community health at Tufts University School of Medicine, who spoke at the Science Summit and serves as editor of Nutrition Today. "It will take all of us working together – from scientists to chefs and product developers to policy makers – before we can really begin to improve public health through flavorful eating."
How Spices and Herbs Potentially Improve Health

• Increase acceptance of healthy foods: James O. Hill, PhD from the University of Colorado and the Anschutz Health and Wellness Center, presented data demonstrating that adding spices and herbs to reduced-fat meals (lean meats, vegetables and pasta) helped make them more appealing. In fact, some reduced fat dishes with added herbs and spices were rated just as high as the full-fat version. Dr. Hill concluded that adding spices and herbs to reduced-fat meals may make them more acceptable to people who struggle with long-term dietary changes to reduce fat.
  
• Adhere to lower-sodium eating plans: Spices and herbs have the potential to help the public meet dietary guidelines for sodium without sacrificing taste. A research study conducted at Johns Hopkins found that an intervention addressing behaviors, including adding spices and herbs to food, resulted in lower sodium intake when compared to those who did not have behavioral intervention. Those participants using spices and herbs consumed an average of 966 mg/day of sodium less than the group that didn't receive the intervention.
  
• Enhance energy metabolism and satiety: Margriet Westerterp-Plantenga, PhD from Maastricht University reviewed research showing that culinary amounts of red pepper increased energy expenditure and satiety in healthy adults. She concluded that red pepper may assist individuals who are trying to manage their weight.
  
• Reduce cardiovascular risk factors: Sheila West, PhD from The Pennsylvania State University provided an overview of research that found a spice blend added to a high-fat meal decreased post-meal insulin and triglyceride levels compared to the same meal without added spices. David Heber, MD, PhD from UCLA shared his research showing that a spice mixture added to hamburger meat helps protect fat from oxidation.
  
• Improve insulin sensitivity: Richard Anderson, PhD from the Beltsville Human Nutrition Research Center presented an overview of the evidence on cinnamon, which indicates that the spice may help improve blood glucose levels and insulin sensitivity.

Tea and citrus products could lower ovarian cancer risk

Research published October 28, 2014  reveals that women who consume foods containing flavonols and flavanones (both subclasses of dietary flavonoids) significantly decrease their risk of developing epithelial ovarian cancer, the fifth-leading cause of cancer death among women.

The research team studied the dietary habits of 171,940 women aged between 25 and 55 for more than three decades.

The team found that those who consumed food and drinks high in flavonols (found in tea, red wine, apples and grapes) and flavanones (found in citrus fruit and juices) were less likely to develop the disease.

Ovarian cancer affects more than 6,500 women in the UK each year. In the United States, about 20,000 women are diagnosed with ovarian cancer each year.

Prof Aedin Cassidy, from the Department of Nutrition at UEA’s Norwich Medical School, led the study. She said: “This is the first large-scale study looking into whether habitual intake of different flavonoids can reduce the risk of epithelial ovarian cancer.

“We found that women who consume foods high in two sub-groups of powerful substances called flavonoids – flavonols and flavanones – had a significantly lower risk of developing epithelial ovarian cancer.

“The main sources of these compounds include tea and citrus fruits and juices, which are readily incorporated into the diet, suggesting that simple changes in food intake could have an impact on reducing ovarian cancer risk.

“In particular, just a couple of cups of black tea every day was associated with a 31 per cent reduction in risk.”

The research was the first to comprehensively examine the six major flavonoid subclasses present in the normal diet with ovarian cancer risk, and the first to investigate the impact of polymers and anthocyanins.

The study was led by Prof Cassidy and Prof Shelley Tworoger, from the Brigham and Women’s Hospital and Harvard Medical School. Data was derived from the Nurses’ Health Study.

‘Intake of dietary flavonoids and risk of epithelial ovarian cancer’ is published in the American Journal of Clinical Nutrition on Nov. 1, 2014. 

Sleep disturbances are linked to higher risk for Alzheimer's disease in men

In a new study, researchers from Uppsala University demonstrate that elderly men with self-reported sleep disturbances run a higher risk of developing Alzheimer's disease than men without self-reported sleep disturbances. The results are published in the scientific journal Alzheimer's & Dementia.

The researchers followed more than 1,000 men, who were initially 50 year old, between the years 1970 and 2010. The results of the study show that self-reported sleep disturbances were linked to an increased risk for Alzheimer's disease during the 40-year follow-up period, particularly if they occurred late in life. The data suggest that a regular good night's sleep could support brain health in men.

'We demonstrate that men with self-reported sleep disturbances run a 1.5-fold higher risk to develop Alzheimer's disease than those without reports of sleep disturbances during a 40-year follow-up period. The later the self-reported sleep disturbance was found the higher the risk was for developing Alzheimer's disease. These findings suggest that strategies aimed at improving sleep quality in late life may help reduce the risk to develop Alzheimer's disease', says Christian Benedict, sleep researcher at Uppsala University, who led the study.

"Importantly, there are several lifestyle factors, such as exercise, that can influence your brain's health. Thus, it must be borne in mind that a multifaceted lifestyle approach comprising good sleep habits is essential for maintaining brain health as you age", says Christian Benedict.

Asthmatics with Vitamin D deficiency are 25 percent more likely to experience acute attacks

Asthma, which inflames and narrows the airways, has become more common in recent years. While there is no known cure, asthma can be managed with medication and by avoiding allergens and other triggers. A new study by a Tel Aviv University researcher points to a convenient, free way to manage acute asthmatic episodes — catching some rays outside. According to a paper recently published in the journal Allergy, measuring and, if need be, boosting Vitamin D levels could help manage asthma attacks. The research, conducted by Dr. Ronit Confino-Cohen of TAU's Sackler Faculty of Medicine, Meir Medical Center, and the Clalit Research Institute, and Dr. Becca Feldman of the Clalit Research Institute drew on the records of millions of patients and used physician diagnoses, rather than self-reports, for evidence of asthma episodes. "Vitamin D has significant immunomodulatory effects and, as such, was believed to have an effect on asthma — an immunologically mediated disease," said Dr. Confino-Cohen. "But most of the existing data regarding Vitamin D and asthma came from the pediatric population and was inconsistent. Our present study is unique because the study population of young adults is very large and 'uncontaminated' by other diseases." A broad study Dr. Confino-Cohen and her team of researchers analyzed the medical records of nearly four million members of Clalit Health Services, Israel's largest health care provider. The Vitamin D levels of 307,900 people were measured between 2008 and 2012. Researchers also took into account key predictors of asthma, such as obesity, smoking, and other chronic diseases. Of some 21,000 asthma patients in Israel studied, those with a Vitamin D deficiency were 25 percent more likely than other asthmatics to have had at least one flare-up in the recent past. The researchers found that Vitamin D-deficient asthmatics were at a higher risk of an asthma attack. "Uncontrolled asthma" was defined as being prescribed at least five rescue inhalers, one prescription of oral corticosteroids, or visiting the doctor for asthma at least four times in a single year. "Our results add more evidence to the link between Vitamin D and asthma, suggesting beneficial effects of Vitamin D on asthma exacerbations," said Dr. Confino-Cohen. "We expect that further prospective studies will support our results. In the meantime, our results support a recommendation for screening of Vitamin D levels in the subgroup of asthma patients who experience recurrent exacerbations. In those with Vitamin D deficiency, supplementation may be necessary." Sunny side up? While most of the Vitamin D in people's bodies comes from exposure to the sun, dermatologists recommend obtaining the ingredient from other sources — fish, eggs, cod liver oil, fortified milk, or a dietary supplement — due to the dangers of overexposure to the sun. "We know a lot about this disease and many therapeutic options are available. So it's quite frustrating that the prevalence of asthma is not decreasing and many patients suffer exacerbations and significant impairment in their quality of life," Dr. Confino-Cohen, an allergy and clinical immunology specialist, said. "Increasing Vitamin D levels is something we can easily do to improve patients' quality of life." Based on the findings, the researchers recommend that people whose asthma cannot be controlled with existing treatments have their Vitamin D levels tested. For those with a vitamin D deficiency, supplements may make sense. "This study provided an exceptional opportunity to research asthma. I received a research grant from Clalit Health Services, which provided us with the opportunity to use their very large database and to conduct the study with the professional staff of Clalit Research Institute," said Dr. Confino-Cohen. "We anticipate further prospective research that will support our findings and open a new treatment modality to the population of uncontrolled asthmatics."

Eating Meat Promotes Colon Cancer, Eating Plants Fights It

A team of Children’s Hospital and Research Center Oakland (CHORI) researchers has found that a category of lipids known as sphingolipids may be an important link in the relationship between diet, inflammation and cancer.   In a paper published online this week in the Journal of Clinical Investigation, Dr. Julie Saba, MD, PhD and her team provide evidence that a sphingolipid metabolite called sphingosine-1-phosphate (S1P) found in both mammalian food products and generated by normal human cells can contribute to inflammation of the colon, inflammatory bowel disease (IBD) and inflammation-associated colon cancer, whereas soy and plant-type sphingolipids called sphingadienes may protect against these conditions.

A connection between inflammation and cancer has been recognized for over a hundred years. This connection is particularly evident in colon carcinogenesis, because patients with IBD have a higher incidence of colon cancer than the general population. There is increasing evidence that inflammation contributes to the earliest stages of carcinogenesis, namely in the process of cell transformation, where the cell acquires many aspects of cancer characteristics. The observation that IBD and colon cancer incidence rise as nations industrialize suggests that changes in diet and nutrition contribute to colitis and colitis-associated colon cancer. 

Bioactive sphingolipids play fundamental roles in carcinogenesis via their ability to regulate programmed cell death pathways, stress responses, immunity, and inflammation. The impact of sphingolipid metabolism is particularly germane in colon cancer, as gut epithelial cells are exposed to sphingolipid metabolites generated by the breakdown of dietary sphingolipids. S1P, the final breakdown product of mammalian sphingolipids, is a pro-inflammatory signaling lipid that promotes cell growth and carcinogenesis. During malignant transformation and colon cancer progression, genetic changes occur in the gut tissues, including an increase in the enzyme that generates S1P and a decrease in S1P lyase (SPL), the enzyme that catalyzes S1P degradation. These changes lead to accumulation of S1P in the gut mucosa.

To explore the impact of S1P accumulation on inflammation and carcinogenesis, the researchers produced a mouse lacking SPL in the gut tissues. They then characterized its responses using a chemical-induced model of colitis-associated colon cancer. Compared to control mice, the mutated mice exhibited more inflammation and a higher incidence of tumors on this regimen. Using a combination of mouse and cell culture experiments, the scientists identified a cascade of steps downstream of S1P that lead eventually to the silencing of two tumor suppressing proteins whose functions are to protect against the formation of cancer. 

In contrast to the cancer-promoting effects of S1P, the researchers showed that soy or plant-type sphingolipids called sphingadienes cannot be metabolized to S1P and instead enhance the metabolism of S1P by increasing SPL levels in gut tissues when fed to mice. Further, sphingadiene treatment of mice reduced inflammation, signs of IBD, and the incidence of tumors. Finally, the researchers showed an increase in S1P-related gene expression in the colons of patients with IBD compared to controls. 

The research suggests that while mammalian sphingolipids may promote inflammation and carcinogenesis, plant/soy sphingolipids cannot be converted into S1P, are anti-inflammatory and reduce the activity of several cancer signaling pathways. The data suggests that dietary sphingolipids may enhance or inhibit colon carcinogenesis, depending on their ability to be metabolized to S1P.  The findings reveal a mechanistic link between diet, inflammation and cancer and provide evidence supporting the further investigation of sphingadienes as colon cancer chemopreventive agents in patients at risk, such as children and adults with IBD.

Dietary cocoa flavanols reverse age-related memory decline

Dietary cocoa flavanols -- naturally occurring bioactives found in cocoa -- reversed age-related memory decline in healthy older adults, according to a study led by Columbia University Medical Center (CUMC) scientists. The study, published today in the advance online issue of Nature Neuroscience, provides the first direct evidence that one component of age-related memory decline in humans is caused by changes in a specific region of the brain and that this form of memory decline can be improved by a dietary intervention.

The researchers point out that the product used in the study is not the same as chocolate, and they caution against an increase in chocolate consumption in an attempt to gain this effect.

As people age, they typically show some decline in cognitive abilities, including learning and remembering such things as the names of new acquaintances or where one parked the car or placed one's keys. This normal age-related memory decline starts in early adulthood but usually does not have any noticeable impact on quality of life until people reach their fifties or sixties. Age-related memory decline is different from the often-devastating memory impairment that occurs with Alzheimer's, in which a disease process damages and destroys neurons in various parts of the brain, including the memory circuits.

A cocoa flavanol-containing test drink prepared specifically for research purposes was produced by the food company Mars, Incorporated, which also partly supported the research, using a proprietary process to extract flavanols from cocoa beans. Most methods of processing cocoa remove many of the flavanols found in the raw plant.

In the CUMC study, 37 healthy volunteers, ages 50 to 69, were randomized to receive either a high-flavanol diet (900 mg of flavanols a day) or a low-flavanol diet (10 mg of flavanols a day) for three months. 

Brain imaging and memory tests were administered to each participant before and after the study. The brain imaging measured blood volume in the dentate gyrus, a measure of metabolism, and the memory test involved a 20-minute pattern-recognition exercise designed to evaluate a type of memory controlled by the dentate gyrus.

"When we imaged our research subjects' brains, we found noticeable improvements in the function of the dentate gyrus in those who consumed the high-cocoa-flavanol drink," said lead author Adam M. Brickman, PhD, associate professor of neuropsychology at the Taub Institute.

The high-flavanol group also performed significantly better on the memory test. "If a participant had the memory of a typical 60-year-old at the beginning of the study, after three months that person on average had the memory of a typical 30- or 40-year-old," said Dr. Small. He cautioned, however, that the findings need to be replicated in a larger study -- which he and his team plan to do.

Flavanols are also found naturally in tea leaves and in certain fruits and vegetables, but the overall amounts, as well as the specific forms and mixtures, vary widely.

The precise formulation used in the CUMC study has also been shown to improve cardiovascular health. Brigham and Women's Hospital in Boston recently announced an NIH-funded study of 18,000 men and women to see whether flavanols can help prevent heart attacks and strokes.

The researchers point out that the product used in the study is not the same as chocolate, and they caution against an increase in chocolate consumption in an attempt to gain this effect.

Two innovations by the investigators made the study possible. One was a new information-processing tool that allows the imaging data to be presented in a single, three-dimensional snapshot, rather than in numerous individual slices. The tool was developed in Dr. Small's lab by Usman A. Khan, an MD-PhD student in the lab, and Frank A. Provenzano, a biomedical engineering graduate student at Columbia. The other innovation was a modification to a classic neuropsychological test, allowing the researchers to evaluate memory function specifically localized to the dentate gyrus. .

Besides flavanols, exercise has been shown in previous studies, including those of Dr. Small, to improve memory and dentate gyrus function in younger people. In the current study, the researchers were unable to assess whether exercise had an effect on memory or on dentate gyrus activity. "Since we didn't reach the intended VO2max (maximal oxygen uptake) target," said Dr. Small, "we couldn't evaluate whether exercise was beneficial in this context. This is not to saythat exercise is not beneficial for cognition. It may be that older people need more intense exercise to reach VO2max levels that have therapeutic effects."