Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

All low-fat diets are not equal

03.05.2005


A low-fat diet rich in vegetables, fruits, whole grains and beans has twice the cholesterol-lowering power of a conventional low-fat diet, according to a new study from the Stanford University School of Medicine.



In other words, a meal of spinach salad, egg and oatmeal-carrot cookies is healthier for your heart than stir-fried lean beef and asparagus and low-fat chocolate chip cookies - even when both meals contain the same amount of saturated fat and cholesterol.

The finding, published in the May 3 issue of the Annals of Internal Medicine, comes from a meticulous comparison of two low-fat diets. One, the conventional diet, focused solely on avoiding harmful saturated fat and cholesterol. Diners ate such foods as frozen waffles and turkey bologna sandwiches. The second diet included the same proportions of fat and cholesterol, plus lots of plant-based foods in accordance with American Heart Association guidelines. Those diners ate such foods as hot grain cereals and vegetable soups.


Both diets lowered total and low-density lipoprotein (LDL, or "bad") cholesterol over the course of the four-week study. The conventional diet produced, on average, a 4.6 percent LDL decrease. But the plant-based diet beat that hands-down: It achieved, on average, a 9.4 percent decrease in LDL. Researchers found no significant differences in changes in triglycerides or high-density lipoprotein ("good") cholesterol.

"The effect of diet on lowering cholesterol has been really minimized and undermined by a lot of clinicians and researchers saying, ’Yes, it has an effect but it’s really trivial: It would be better to put you on drugs to control your cholesterol,’" said Christopher Gardner, PhD, assistant professor (research) of medicine at the Stanford Prevention Research Center and lead author on the National Institutes of Health-funded study. "But we think part of the reason was that we weren’t really giving diet a fair shake. We were so focused on the negative-just what to avoid-and not what to include."

The bottom line? Mother knows best: Do eat your veggies - and other nutrient - dense foods. It’s not enough to simply steer clear of saturated fat and cholesterol.

"We would really hope that people would appreciate the new American Heart Association Guidelines," said Gardner, who decorates his office with splashy posters of squashes and peas. "Include more whole grains and vegetables and beans and colors - not iceberg lettuce, but red bell peppers and carrots and broccoli and red cabbage and the really colorful foods. Those are all really low in saturated fat and cholesterol, and they’re really high in other nutrients and phytochemicals that are good for you."

A "plant-based" diet is not necessarily a vegetarian diet. It simply includes a foundation of whole grains, vegetables, beans, nuts, seeds and fruits. The 2000 AHA guidelines recommend at least five daily servings of vegetables and fruits and at least six daily servings of grains with an emphasis on whole grains.

Previous studies, Gardner said, have shown plant-based diets to be effective in lowering cholesterol. But plant-based eaters also tend to consume less saturated fat and cholesterol than conventional low-fat eaters.

The Stanford study breaks new ground by comparing two patient groups eating different foods but identical amounts of total and saturated fat, protein, carbohydrate and cholesterol. So the two groups’ different levels of blood cholesterol change are attributable to the different foods - dark green salads and bean burritos, for example, versus iceberg lettuce and frozen pizza - and not differences in saturated fat and cholesterol intake.

The randomized clinical trial included 120 adults, ages 30 to 65. All were members of the target population for food-based approaches to lowering cholesterol: They had moderately high LDL levels, between 130 and 190 mg/dL. Researchers randomly divided the outpatients into two diners’ groups: 61 ate the conventional diet, while 59 ate the plant-based diet. Each weekday for a month, they visited a research dining hall for a specially prepared, carefully weighed, chemically analyzed lunch or dinner.

The study required that participants maintain a constant weight so that any changes in blood cholesterol would be attributable to the diets themselves-not to any changes in weight brought on by the diets. When changes in weight were observed, the participants’ calories were changed accordingly to help them stay stable. In general researchers tended to add calories to the meal plan over the course of the study as participants were observed to be more likely to lose weight than to gain weight on both diets.

The scientists also requested that no one change exercise habits, saying: "If you are a marathon runner, keep running marathons. But if you’re a couch potato, we need you to stay a couch potato."

Gardner, a 20-year vegetarian who specializes in nutrition and preventive medicine, expects a plant-based diet combined with weight loss and exercise to achieve even more impressive cholesterol-lowering results. Plus, he said, people can eat even less saturated fat and cholesterol than the study participants did.

Susan Ipaktchian | EurekAlert!
Further information:
http://www.mednews.stanford.edu

More articles from Studies and Analyses:

nachricht Do microplastics harbour additional risks by colonization with harmful bacteria?
05.04.2018 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>