A Low-Carb Diet Or A Low-Fat Diet?

You won't find the answer to that question in the ADA's new Nutrition Recommendations:

Nutrition Recommendations And Interventions For Diabetes, A Position Statement Of The American Diabetes Association, Diabetes Care, January 2008

You will however find the ADA's first official endorsement of low-carbohydrate diets, a stand they previously shied away from owing to lack of evidence on safety and effectiveness:

"For weight loss, either low-carbohydrate or low-fat calorie-restricted diets may be effective in the short term (up to 1 year)."
- ADA 2008 Position Statement

Their support for a low-carb eating plan, albeit for one year, isn't so much the highlight of these new recommendations as is their support for individualized meal plans. Speaking in a press release that accompanied the Position Statement, Ann Albright, ADA President of Health Care & Education said:¹

"The evidence is clear that both low-carbohydrate and low-fat calorie restricted diets result in similar weight loss at one year. We're not endorsing either of these weight-loss plans over any other method of losing weight. What we want health-care providers to know is that it's important for patients to choose a plan that works for them."
Ann Albright, PhD, RD, President, Health Care & Education, ADA

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¹ ADA press release, December 28, 2007:
ADA Issues New Clinical Practice Recommendations, New Advice for Doctors About Low-Fat, Low-Carb Restricted Diets For Short-Term Weight Loss

Vegan Diet Outshines ADA Diet

Since we had the honor of an e-visit from the distinguished Dr. Neal Barnard, and in light of our previous post describing the suspension of the intensive blood glucose treatment arm (medication-based) of the large ACCORD trial, I present the findings of one of Dr. Barnard's more recent studies - one that finds benefit without the use of drugs.

Barnard, et al's study which appeared in the August 2006 issue of Diabetes Care,¹ found that people with diabetes who followed a low-fat, vegan diet saw improvements in HbA1c, body weight, BMI, waist circumference, total cholesterol, and LDL cholesterol that were significantly greater than improvements in a group following an ADA diet (which adhered to American Diabetes Association guidelines).

Participants (n=99) were followed for 22 weeks, at the end of which:

"Among participants whose diabetes medications remained unchanged throughout, A1C fell 1.23 points in the vegan group and 0.38 points in the ADA group (P = 0.01)."

"Body weight decreased 6.5 kg (14.3 lbs) in the vegan group and 3.1 kg (6.8 lbs) in the ADA group (P < 0.001)."

"Among those who did not change lipid-lowering medications, LDL cholesterol fell 21.2% in the vegan group and 10.7% in the ADA group (P = 0.02)."

A vegan diet includes grains, legumes, vegetables, and fruits, and excludes animal products. The vegan diet in this study also excluded added fats.



Click for larger.________
¹ A Low-Fat Vegan Diet Improves Glycemic Control and Cardiovascular Risk Factors in a Randomized Clinical Trial in Individuals With Type 2 Diabetes

Photo of vegan pyramid: Nutrispeak.com, the home page of Vesanto Melina, MS RD.

Trans-Fat Alternative Fares Poorly In Study

Trans-fat, like saturated fat and dietary cholesterol, has been found to raise LDL cholesterol, increasing risk for heart disease. Trans-fats may also increase insulin resistance in people with diabetes. (See Trans Fatty Acids And Insulin Resistance.)

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) recommends that people with diabetes limit intake of foods with trans-fat, such as snack foods and commercially baked goods.

But how healthy are the fats being used to replace trans-fats?

A study that appeared in the January 15th issue of Nutrition & Metabolism tested the effects of interesterified fats (IE fats), one of the leading contenders to replace trans-fats. Thirty participants consumed diets that were either rich in palm olein*, trans-fat, or IE fat. After 4 weeks:

• Those on the trans-fat and IE fat diets had higher LDL/HDL cholesterol ratios than those on the palm olein diet.
  
• Those on the trans-fat and IE fat diets had higher fasting plasma glucose than those on the palm olein diet. (Those eating trans-fat had a BG increase of about 5.2 mg/dl after 4 weeks, those eating IE fat had a BG increase of about 18.9 mg/dl.)

Manufacturers are still working to find a good replacement for trans-fats. What this study tells us is that not all apparently healthy alternatives to trans-fats are good ones.

*Palm olein is the fraction of palm oil that is liquid at room temperature. Palm olein is approximately 45% saturated fat and 55% unsaturated fat. (American Palm Oil Council)

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For the study (full free access):
Stearic Acid-Rich Interesterified Fat And Trans-Rich Fat Raise The LDL/HDL Ratio And Plasma Glucose Relative To Palm Olein In Humans

Menu Planners

It's a new year. Maybe you've resolved to hold your meals to a new standard. If so, you might want to check out the National Heart, Lung and Blood Institute's (NHLBI) Menu Planner.

It lets you select a daily calorie limit and plan your meals with drop-down menus. The planner keeps a running tally of your total calories, fat, and carbohydrates ... and lets you know when you've exceeded your calorie limit.

It's easy to use, although for what it provides in ease it lacks in depth. The food choices are limited. (Where are the nuts? Has anyone seen the nuts?)

A better tool for analyzing your food intake can be found on the USDA's MyPyramid Tracker site. For example, an entry of "pizza" in the search box returns 66 items, where the NHLBI's Menu Planner fails to list pizza at all.

Both sites are worth a visit, though. While you're at the NHLBI's site, don't miss their Portion Distortion Interactive Quiz:

Mangoes and Diabetes

While I'm talking about how food components may affect blood glucose, I thought I'd pass along this news coming out of the Third Australian Health and Medical Research Congress in Melbourne this week. (November 26 - December 1).

Researchers presenting at the Congress are reporting preliminary study findings which suggest components in mangoes may act on the same receptors (peroxisome proliferator-activated receptors, or PPARs) as some common diabetes medications. (GlaxoSmithKline's Avandia® acts on PPARs.)

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For a study abstract (Enter the term "mangoes" in the Abstract Search box.):
Australian Health and Medical Research Congress - MELBOURNE CONVENTION CENTRE

For a news summary:
Mangoes for Diabetes?

Yogurt May Moderate Post-meal Blood Sugar

Researchers at the University of Massachusetts Amherst analyzed samples of dairy and soy yogurts. They found ...

" ...that fruit-enriched yogurts - especially those made with blueberries or made from soy - contain active natural compounds that may curb some aspects of diabetes."

Specifically, the yogurts inhibited the action of two enzymes, α-amylase and α-glucosidase, which break down carbohydrates into a form that is easily absorbed. The result is a reduced spike in blood glucose following a meal.

The researchers also found that soy yogurts acted as ACE inhibitors, stalling the action of Angiotensin-I converting enzyme or ACE-I, an enzyme responsible for constricting blood vessels and contributing to high blood pressure.

The study will appear in the December issue of the Journal of Food Biochemistry.

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For a summary of the study:
Fruit Yogurt Could Play Important Role in Diabetes Management, UMass Amherst Scientists Report

For the study (abstract):
Potential of Select Yogurts for Diabetes and Hypertension Management

Heme Iron Intake Linked to Diabetes

Iron's link to diabetes has been in the news over the last few years.

In February, 2004, a study that appeared in the Journal of the American Medical Association found that high levels of iron in the body almost tripled women's risk for developing diabetes. Researchers had examined iron stores in over 32,000 women who took part in the Nurses' Health Study and followed them for 10 years.

Recently, a study which appears in this month's issue of Diabetes Care found that women with high intakes of heme iron - the kind found primarily in meat - had a 28% greater risk of developing diabetes than women whose meat intake was lower. Researchers examined dietary intake of over 85,000 women who took part in the Nurses' Health Study and followed them for 20 years.

One item to note - This recent study found no association between diabetes and iron intake from supplements, iron intake from non-heme sources (such as spinach and other greens, beans, and fortified cereals), or total iron intake from all sources. It could only document a link between diabetes and the intake of heme iron. (Heme iron is a constituent of hemoglobin and myoglobin molecules in animals. Only about 40% of the total iron supplied by meat is in the heme form.)

Although this study investigated iron's association with the risk for developing diabetes, it did not reveal a mechanism, nor did it discuss what effect intake of heme iron would have in those already dealing with the disease. However, in an interview with Reuters Health, one of its authors theorized:

"In excess, these molecules create a state of "oxidative stress" that damages body cells over time. Oxidative stress could theoretically set the stage for diabetes by reducing body cells' sensitivity to the hormone insulin, Rajpathak explained."
- More evidence ties iron intake to diabetes risk

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For the 2004 JAMA study:
Body Iron Stores in Relation to Risk of Type 2 Diabetes in Apparently Healthy Women

For a news summary of the JAMA study:
Diabetes risk may be associated with elevated iron levels

For the June, 2006 Diabetes Care study:
Iron Intake and the Risk of Type 2 Diabetes in Women

Resistant Starch and Soluble Fiber Lower Post-meal Glucose

The evidence continues to mount on the benefits of resistant starch and soluble fiber (beta-glucan).

In a study published in the May issue of Diabetes Care, researchers saw:

Reductions in after-meal glucose:

• From resistant starch - 24%
  
• From soluble fiber - 17%
  
• From a combination of resistant starch and soluble fiber - 33%

Reductions in after-meal insulin:

• From resistant starch - 38%
  
• From soluble fiber - 33%
  
• From a combination of resistant starch and soluble fiber - 59%

Our previous post on resistant starch includes a description and food sources.

Beta-glucan, the type of soluble fiber tested in this study, is found naturally in foods such as oats, barley, dried beans and peas, mushrooms, flax seed, psyllium seed husks, and baker's yeast.

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For the study:
Consumption of Both Resistant Starch and ß-Glucan Improves Postprandial Plasma Glucose and Insulin in Women

FDA to Define "Whole Grains"

The Dietary Guidelines for Americans, 2005, recommends that Americans consume 3 or more servings of whole grains per day, with a goal of at least half of their grains coming from whole grains.

But what's a "whole grain"?

The FDA has issued a draft document intended "to provide guidance to industry about what the agency considers to be "whole grain" and to assist manufacturers in labeling their products."

In general, a "whole grain" may be ground, cracked, flaked, or intact - but should consist of the grain's bran, germ, and starchy endosperm in the same proportions that they exist in the original grain.

Examples of whole grains:

• Amaranth
  
• Barley
  
• Buckwheat
  
• Bulgur
  
• Corn (including popcorn)
  
• Millet
  
• Quinoa
  
• Rice
  
• Rye
  
• Oats (including rolled oats)
  
• Sorghum
  
• Teff
  
• Triticale
  
• Wheat
  
• Wild rice

Examples of foods not considered whole grains:

• Flours or meals (e.g. corn meal) are not considered whole grain unless the bran and germ, as well as the starchy interior are present.
  
  
• Soybeans, chickpeas, and other beans and legumes are not considered whole grains.
  
  
• Barley that is pearled is not considered a whole grain because some of the bran layer has been removed.

You can read the rest of the FDA's draft guidance statement on whole grains here.

"Can I Get You a Drink?"

The Holidays are here. You may find yourself on the receiving end of that question more often. If you have diabetes and take insulin or oral diabetes medications, keep in mind that alcohol can lower blood glucose.

How Alcohol Affects Blood Glucose

Normally, when you skip a meal, the liver will break down stored carbohydrate and send glucose out through the bloodstream to energy-hungry tissues until you eat again. Alcohol can disrupt this process:

"Your body reacts to alcohol like a poison. The liver wants to clear it from the blood quickly. In fact, the liver won't put out glucose again until it has taken care of the alcohol. If your blood glucose level is falling, you can quickly wind up with very low blood sugar."
- From the ADA's fact sheet on Alcohol

So if you're offered a drink, heed the ADA's advice:

• Never drink alcohol on an empty stomach.
  
• Limit yourself to 1 drink if you're a woman or 2 drinks if you are a man.

Visit the ADA's site for more, including wise drink choices and mixing alcohol with exercise.

Encourage Healthy Weight in Your Children

The Baylor College of Medicine has published a brochure to help families deal with issues of overweight in its younger members.

It discusses the causes of overweight in children and offers solutions that involve the whole family.

It's short, easy to read, and full of great tips, including:

• Plan parties and vacations around movement and play.
  
• When taking part in activities, emphasize fun, not skill.
  
• Don’t draw attention to healthy foods you’ve purchased.
  
• In restaurants or cafeterias - Choose smaller sizes, share side orders, set aside half of a restaurant dinner for lunch the next day.
  
• Don’t overly restrict sweets or treats—try “everyday” and “sometimes” foods.

And it's available free online:

English version (pdf):
Your Child's Weight
Help Your Child with Successful Weight Management

Spanish version (pdf):
El Peso de Su Hijo
Ayude a su hijo a manejar su peso con exito

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Photo compliments of the Cincinnati Children's Hospital's Young and Healthy magazine. It appears in the magazine's "Ask Dr. Manfroy" column. Dr. Manfroy's response to My overweight child seems to be losing interest in school and activities. Can you help me understand what’s going on? offers additional insight into the sensitive issue of overweight in children.

"Which Diet Works Best?"

That's a popular question around here. Rather than try to argue the merits of one diet over another, I'll point you to a study that appeared in a January 2005 issue of the Journal of the American Medical Association.

The researchers compared the effectiveness of 4 popular diets:

• Atkins (low carbohydrate)
  
• Ornish (low fat)
  
• Weight Watchers (calorie restriction)
  
• Zone (carb/protein/fat balance)

They randomly assigned 160 people to one of the diets above. After a year they assessed their findings.

They found all diets produced a modest weight loss, and all improved scores of cardiovascular health (the more weight the subject lost, the lower his cholesterol, C-reactive protein, and insulin levels) - as long as the participant stuck with the diet. The more extreme diets such as Atkins and Ornish had the greatest drop-out rates.

Maria Adams, author of the summary article I've linked below, included this comparison table:



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For a summary of the study:
Atkins, Ornish, Weight Watchers, and Zone Diets: A Comparison

For the study itself (abstract only, subscription required for full article):
Comparison of the Atkins, Ornish, Weight Watchers, and Zone Diets for Weight Loss and Heart Disease Risk Reduction

Soy for a Healthy Liver

Researchers in Mexico found when they fed hyperinsulinemic rats (rats with high blood levels of insulin) diets high in soy protein, it decreased the amount of fat in the rats' liver.

People with insulin resistance or diabetes are more likely to have higher levels of insulin in their blood. That insulin can lead to increased production of fatty acids in the liver leading to more pockets of fat in liver cells (hepatocytes).

A fatty liver by itself doesn't damage liver cells. But it's sometimes associated with liver inflammation, which can be damaging. The Liver Foundation describes the causes and treatment of fatty liver disease.

How did soy protein protect against fat buildup in the rats' liver? It reduced the expression of certain genes responsible for fat production. It was also capable of increasing the breakdown of fat.

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For a summary of the research:
Soy Protein Reduces Effects of Diabetes on Liver

For the research itself:
Appears in the Journal of Lipid Research, September 2005 (abstract only, subscription required for full article)
Soy Protein Reduces Hepatic Lipotoxicity in Hyperinsulinemic Obese Zucker fa/fa Rats

Another Benefit of Olive Oil

We know olive oil is good for the heart. Its monounsaturated fats have a reputation for lowering LDL (bad cholesterol) and raising HDL (good cholesterol).

Now, researchers have found another benefit of olive oil - the ability to reduce pain and inflammation, much like non-steroidal anti-inflammatory drugs (NSAIDs) such as Advil® or Motrin® can.

This time the benefit is not due to olive oil's monounsaturated fats, but to a newly discovered chemical the researchers named oleocanthal. It was found occurring naturally in the extra-virgin type of olive oil.

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For a summary of the researchers' findings:
Olive Oil Contains Natural Anti-inflammatory Agent

The article appears in the September 1 issue of the journal Nature (editor's summary only, subscription required for full article.):
Phytochemistry: Ibuprofen-like Activity in Extra-virgin Olive Oil

MyPyramid

The USDA unveiled a new website to accompany their new food guide pyramid back in April. It's worth a visit. You can get a personalized meal plan by entering your age, gender, and physical activity level. There's even a place to keep track of your meals along with nutrient analysis and recommendations.

Go to www.MyPyramid.gov.