Whole diet approach to lower cardiovascular risk has more evidence than low-fat diets

A study published in The American Journal of Medicine reveals that a whole diet approach, which focuses on increased intake of fruits, vegetables, nuts, and fish, has more evidence for reducing cardiovascular risk than strategies that focus exclusively on reduced dietary fat.This new study explains that while strictly low-fat diets have the ability to lower cholesterol, they are not as conclusive in reducing cardiac deaths. By analyzing major diet and heart disease studies conducted over the last several decades, investigators found that participants directed to adopt a whole diet approach instead of limiting fat intake had a greater reduction in cardiovascular death and non-fatal myocardial infarction.Early investigations of the relationship between food and heart disease linked high levels of serum cholesterol to increased intake of saturated fat, and subsequently, an increased rate of coronary heart disease. This led to the American Heart Association’s recommendation to limit fat intake to less than 30% of daily calories, saturated fat to 10%, and cholesterol to less than 300 mg per day.”Nearly all clinical trials in the 1960s, 70s and 80s compared usual diets to those characterized by low total fat, low saturated fat, low dietary cholesterol, and increased polyunsaturated fats,” says study co-author James E. Dalen, MD, MPH, Weil Foundation, and University of Arizona College of Medicine. “These diets did reduce cholesterol levels. However they did not reduce the incidence of myocardial infarction or coronary heart disease deaths.”Carefully analyzing studies and trials from 1957 to the present, investigators found that the whole diet approach, and specifically Mediterranean-style diets, are effective in preventing heart disease, even though they may not lower total serum or LDL cholesterol. The Mediterranean-style diet is low in animal products and saturated fat, and encourages intake of monounsaturated fats found in nuts and olive oil. In particular, the diet emphasizes consumption of vegetables, fruit, legumes, whole grains, and fish.”The potency of combining individual cardioprotective foods is substantial — and perhaps even stronger than many of the medications and procedures that have been the focus of modern cardiology,” explains co-author Stephen Devries, MD, FACC, Gaples Institute for Integrative Cardiology (Deerfield, IL) and Division of Cardiology, Northwestern University (Chicago, IL). “Results from trials emphasizing dietary fat reduction were a disappointment, prompting subsequent studies incorporating a whole diet approach with a more nuanced recommendation for fat intake.”Based on the data from several influential studies, which are reviewed in the article, Dalen and Devries concluded that emphasizing certain food groups, while encouraging people to decrease others, is more cardioprotective and overall better at preventing heart disease than a blanket low-fat diet. Encouraging the consumption of olive oil over butter and cream, while increasing the amount of vegetables, fruits, whole grains, nuts, and fish promises to be more effective.”The last fifty years of epidemiology and clinical trials have established a clear link between diet, atherosclerosis, and cardiovascular events,” concludes Dr. …

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Ease of access improves fruit and vegetable consumption

Sep. 3, 2013 — Low-income communities have particular problems getting adequate fruits and vegetables because of limited access to supermarkets and farmers markets. A new study from Wake Forest Baptist Medical Center shows that community-supported agriculture (CSA) programs may be a feasible approach for providing fresh fruits and vegetables to under-resourced communities.Lead author Sara A. Quandt, Ph.D., a professor of epidemiology and prevention at Wake Forest Baptist, said that CSAs, which link consumers to a local farm’s produce over a growing season, have been proposed as a solution for disparities in fruit and vegetable consumption, though evaluation of such efforts has been limited. The typical U.S. diet fails to meet daily recommendations for fruit and vegetable consumption.This CSA program, Farm Fresh Healthy Living of Forsyth County, N.C., was developed, administered, and evaluated by a partnership of university researchers, Experiment in Self Reliance Inc., a community nonprofit agency, and Harmony Ridge Farms, a Forsyth County, N.C., farm using organic practices.”Expanding access to healthful foods is an important step in reducing health disparities,” said Quandt. “The objective of this study was to test the feasibility of a CSA program for low-income families in Forsyth County.”The study appears last month in the Centers for Disease Control and Prevention’s journal Preventing Chronic Disease.For a small randomized, controlled feasibility study, Quandt and fellow researchers recruited 50 low income women with children, then divided them into an intervention group and a control group of 25 each. The participants ranged in age from 24 to 60; most were African-American and unmarried.Intervention participants received a free box of fresh produce for 16 weeks from May through August 2012. They were also offered five educational sessions, including cooking classes, a farm tour and a grocery store tour with a dietitian that focused on healthful eating on a budget. The control participants did not receive education or the produce boxes.The researchers observed a significant increase over the summer in the number of different fruits and vegetables in the households of the intervention group compared with the control group. …

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A grassy trend in human ancestors’ diets

June 3, 2013 — Most apes eat leaves and fruits from trees and shrubs. New studies spearheaded by the University of Utah show that human ancestors expanded their menu 3.5 million years ago, adding tropical grasses and sedges to an ape-like diet and setting the stage for our modern diet of grains, grasses, and meat and dairy from grazing animals.In four new studies of carbon isotopes in fossilized tooth enamel from scores of human ancestors and baboons in Africa from 4 million to 10,000 years ago, a team of two dozen researchers found a surprise increase in the consumption of grasses and sedges — plants that resemble grasses and rushes but have stems and triangular cross sections.”At last, we have a look at 4 million years of the dietary evolution of humans and their ancestors,” says University of Utah geochemist Thure Cerling, principal author of two of the four new studies published online June 3 by the journal Proceedings of the National Academy of Sciences. Most funding was from the National Science Foundation.”For a long time, primates stuck by the old restaurants — leaves and fruits — and by 3.5 million years ago, they started exploring new diet possibilities — tropical grasses and sedges — that grazing animals discovered a long time before, about 10 million years ago” when African savanna began expanding, Cerling says. “Tropical grasses provided a new set of restaurants. We see an increasing reliance on this new resource by human ancestors that most primates still don’t use today.”Grassy savannas and grassy woodlands in East Africa were widespread by 6 million to 7 million years ago. It is a major question why human ancestors didn’t seriously start exploiting savanna grasses until less than 4 million years ago.The isotope method cannot distinguish what parts of grasses and sedges human ancestors ate — leaves, stems, seeds and-or underground storage organs such as roots or rhizomes. The method also can’t determine when human ancestors began getting much of their grass by eating grass-eating insects or meat from grazing animals. Direct evidence of human ancestors scavenging meat doesn’t appear until 2.5 million years ago, and definitive evidence of hunting dates to only about 500,000 years ago.With the new findings, “we know much better what they were eating, but mystery does remain,” says Cerling, a distinguished professor of geology and geophysics, and biology. “We don’t know exactly what they ate. We don’t know if they were pure herbivores or carnivores, if they were eating fish [which leave a tooth signal that looks like grass-eating], if they were eating insects or if they were eating mixes of all of these.”Why Our Ancestor’s Diets MatterThe earliest human ancestor to consume substantial amounts of grassy foods from dry, more open savannas “may signal a major and ecological and adaptive divergence from the last common ancestor we shared with African great apes, which occupy closed, wooded habitats,” writes University of South Florida geologist Jonathan Wynn, chief author of one of the new studies and a former University of Utah master’s student.”Diet has long been implicated as a driving force in human evolution,” says Matt Sponheimer, a University of Colorado, Boulder anthropologist, former University of Utah postdoctoral fellow and lead author of the fourth study.He notes that changes in diet have been linked to both larger brain size and the advent of upright walking in human ancestors roughly 4 million years ago. …

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KISS ME DEADLY proteins may help improve crop yields

May 27, 2013 — Dartmouth College researchers have identified a new regulator for plant hormone signaling — the KISS ME DEADLY family of proteins (KMDs) – that may help to improve production of fruits, vegetables and grains.


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The study’s results will be published the week of May 27 in the journal Proceedings of the National Academy of Sciences.

Professor G. Eric Schaller, the paper’s senior author, studies the molecular mechanisms by which a plant recognizes a hormone and then responds to it. Among the hormones he studies are “anti-aging” cytokinins, which play critical roles in regulating plant growth and development, including stimulating yield, greening, branching, metabolism and cell division. Cytokinins are used in agriculture for multiple purposes, from crops to golf course greens.

In their PNAS paper, the researchers identify KMDs as a new regulator for cytokinin signaling. To regulate plant growth, plants need to perceive cytokinins and convert this information into changes in gene expression. The KMDs target a key group of cytokinin-regulated transcription factors for destruction, thereby regulating the gene expression changes that occur in response to cytokinin. In other words, increases in KMD levels result in a decreased cytokinin response (or less crop growth), while decreases in KMD levels result in a heightened cytokinin response (or greater crop growth).

The results suggest that KMDs represent a natural means by which plants can regulate the cytokinin response and may serve as a method to help regulate agriculturally important cytokinin responses.

“We expect that a better understanding of cytokinin activity and KMDs could lead to improved agricultural productivity,” said Schaller.

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The above story is reprinted from materials provided by Dartmouth College, via EurekAlert!, a service of AAAS.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Hyo Jung Kim, Yi-Hsuan Chiang, Joseph J. Kieber, and G. Eric Schaller. SCFKMD controls cytokinin signaling by regulating the degradation of type-B response regulators. Proceedings of the National Academy of Sciences, 2013; DOI: 10.1073/pnas.1300403110

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