January 20, 2010

Shirataki Noodles, Glucomannan and Konjac Fiber Examined

The Wall Street Journal recently published an article entitled "Noodling Your Way to Weight Loss" that looked at the potential health benefits of konjac fiber, a primary ingredient in Asian Shirataki noodles. Shirataki noodles are very low calorie, almost carbohydrate-free gummy noodles composed mostly of water and glcomannan (another name for konjac fiber). These noodles have gotten a lot of press from weight loss and low carb bloggers as they are a starch product high in fiber but relatively low in calories - here's a smattering:
These products might be low carb or low calorie, but do Shirataki noodles, konjac fiber and glucomannan supplements really promote health? The WSJ article cites a University of Connecticut meta-analysis that looked at 14 studies that shows the fiber does help lower LDL, promotes glucose regulation and mildly affect weight loss. A number of other studies analyzing the effects of konjac glucomannan (KGM) supplements have shown somewhat promising results as well:
  • A Diabetes Care study published in 2000 found that the soluble fiber found in Konjac-mannan based foods does improve glycemic control and lipid profiles
  • A Journal of Nutrition article examined the effect of Konjac-mannan in baboons fed Western diets and determined that use of the supplement decreased triglycerides and increased proportion of HDL to total cholesterol when compared to non Konjac-mannan fortified diets
  • The International Journal of Obesity reported that glucomannan may be helpful in promoting significant weight loss and reducing serum cholesterol and LDL over an eight-week trial period
But these health benefits are the type that are garnered from increasing dietary fiber and soluble fiber intake across the board, not just from one specific supplement or noodle product. The WSJ article quotes Abhimanyu Garg, chief of the division of nutrition and metabolic diseases at the University of Texas Southwestern Medical Center in Dallas. He points out that there's nothing really magical about one type of soluble fiber over another, "If you are eating papayas or apricots or dates, you are increasing soluble fiber while also getting vitamins and minerals". So while Shirataki noodles may be a good source of low-carbohydrate soluble dietary fiber, they most likely don't provide any "miracles" above and beyond that of any other naturally soluble-fiber containing food product.

January 19, 2010

Celebrate Healthy Weight Week

Today is "Rid the World of Fad Diets & Gimmicks Day" and part of Healthy Weight Week, sponsored by the Healthy Weight Network (publisher of the Healthy Weight Journal). Led by Francie M. Berg, adjunct professor at the University of North Dakota School of Medicine, the Healthy Weight Network seeks to provide consumers with "the latest research on obesity, eating disorders, weight and eating issues, dieting, weight loss and weight gain along with practical guideline for healthy living".

The Healthy Weight Network publishes an annual list of "Slim Chance Awards" that highlight the year's most fraudulent and outrageous weight loss claim, weight loss promotion and weight loss gimmick. For 2009, the Slim Chance awards went to:

The Healthy Weight Network also works to help consumers identify weight loss frauds. Citing the American Heart Association's Guidelines for Weight Management for Healthy Adults, the network focuses on food over supplements and states that, "diets rich in complex carbohydrate and fiber are consistent with health promotion and disease prevention in healthy people".

January 12, 2010

Make Half Your Grains Whole

 The Dietary Guidelines for Americans, 2005 are being revised and are slated to be released as the Dietary Guidelines for Americans, 2010 in the fall of this year. The 2005 Dietary Guidelines encourage Americans to "make half your grains whole". But what exactly does this mean?

According to the DHHS and USDA's President's Food Safety Working Group, approximately 50 cents of every food dollar in the US is spent outside the home. With the knowledge that restaurants and ready to eat meals offer very few whole grain options, dietitians and healthcare professionals urge Americans to increase whole grain consumption at home. You can find a list of what is and what is not a whole grain in this previous post.

When selecting whole grain foods for home consumption, there are essentially three areas you can examine at to determine whether or not a food is a good source of whole grain:
  1. Ingredient list: Look for the word "whole" in the first ingredient in the ingredient list; ingredients are listed in order by weight
  2. Dietary fiber: Look for foods that have 3 grams of fiber or more per serving (typically every 100 calories or 1 oz)
  3. Grams of whole grain in foods that are a mix of whole and enriched grains: 16 grams of whole grain ingredients counts as a full serving
Food products are increasingly being labeled with the number of grams of whole grain content. A whole grain product has 16 grams of whole grain per serving; but you may see the Whole Grain Stamp listing half servings of whole grain (8 grams) per serving as well. Keep in mind that high fiber is not always the same as whole grain. Many foods have isolated or functional fibers that are added to traditionally low fiber, enriched grain products.

The Grains group in MyPyramid.gov and the American Dietetic Association recommend that inactive Americans have the following total number of grains per day and that half of these be whole grains:

The American Dietetic Association's Nutrition Fact Sheet "Whole Grains Made Easy" recommends incorporating some of the following foods into your daily routine in an attempt to "make half your grains whole":
  • Whole grain bagel
  • Popcorn
  • Brown rice
  • Whole grain pasta
  • Oatmeal
  • Wild rice
  • Whole grain English muffin
  • Whole grain veggie burger
  • Bulgur pilar
  • Barley mushroom soup
  • Whole grain pizza crust

January 11, 2010

LA Times Weighs in on Functional Fibers

In today's LA Times Health section, columnist Elena Conis tackled the functional vs. intact fiber conundrum facing today's food consumers. Her article, All fibers may not be created equal looked at the lack of evidence that adding fiber to foods from sources like inulin, maltodextrin and polydextrose conveys the same health benefits as intact fiber from whole foods such as fruits, vegetables, whole grains and legumes.

As covered in a previous post on this blog - functional fibers are also called isolated fibers. They are often added to foods that aren't naturally high in fiber in order to boost the food's presumed fiber content. Increasingly, you see isolated fibers added to traditionally low fiber foods, there's High Fiber V8 Vegetable Juice, Progresso High Fiber Canned Soups and most recently, Fiber One's High Fiber Cottage Cheese. While these added fibers may increase the total grams of dietary fiber on a Nutrition Facts Panel, it remains undetermined as to whether or not they are as beneficial for cholesterol lowering, weight loss and blood sugar regulation as are intact fibers.

In the article, both the director of clinical dietetics at the Mayo Clinic and a spokesperson for the American Society for Nutrition confirm what almost all other nutrition professionals do: if you wish to receive the health benefits of dietary fiber, it is better to choose foods that are naturally high in fiber than low fiber foods with fiber added to them. The article goes on to say that isolated or added fibers oftentimes lack vitamins, minerals, plant components and antioxidants that are often found in their whole food counterparts.

January 8, 2010

Duncan Hines 100% Whole Grain Muffin Mixes

Fresh for the New Year comes an innovative integration of fiber in foods you love - even if you aren't so certain it should be there. Duncan Hines has released a line of 100% Whole Grain Muffin Mixes. While it looks like the manufacturer has gone out of its way to ensure you get three grams of dietary fiber per baked muffin - this is by no means one of the best dietary sources of fiber out there.

Five of the six flavors feature Whole Wheat Flour as the first ingredient - an impressive feat given the usual refined wheat nature of processed and packaged mixes. But, in these same five products, sugar shows up as ingredient number two. (In the Triple Chocolate Chunk variety, sugar is ingredient number one and whole wheat flour is number two).

While most dietitians would recommend aiming for three grams of fiber or more per serving of whole grain food - this usually pertains to a 100 calorie serving size and almost never to a food whose second ingredient by weight is pure sugar. If it looks like a cookie and tastes like a cookie.... Unfortunately, each Duncan Hines 100% Whole Grain muffin is going to cost you 200 calories for those same three grams of fiber.

You're better off working on a homemade muffin recipe that you can add whole wheat flour, flaxseed, nuts and fruit to for a more natural dietary fiber boost. If you like muffins but not the chewy texture of packaged mixes, try making these Morning Glory Muffins from Cooking Light. For 185 calories, the three grams of fiber come whole wheat flour, oats and fruit. Compare this to the fiber source of the Duncan Hines mix, which consists of only whole wheat flour and modified corn starch.

Duncan Hines 100% Whole Grain muffin mixes are available in the flavors:
  • 100% Whole Grain Apple Cinnamon with Oatmeal Granola Topping Muffin Mix
  • 100% Whole Grain Blueberry Streusel Muffin Mix
  • 100% Whole Grain Chocolate Chip Muffin Mix
  • 100% Whole Grain Cinnamon Swirl Muffin Mix
  • 100% Whole Grain Triple Chocolate Chunk Muffin Mix
  • 100% Whole Grain Wild Maine Blueberry Muffin Mix