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 New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

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: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Scientists propose synestia, a new type of planetary object

23.05.2017 | Physics and Astronomy

Zap! Graphene is bad news for bacteria

23.05.2017 | Life Sciences

Medical gamma-ray camera is now palm-sized

23.05.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>