Tag Archives: heart healthy

Cheerios, Soluble Fiber and Your Heart

IMG_3239The skeptical cardiologist usually eschews the breakfast offerings in the Doctor’s lounge. I’m not really interested in consuming donuts, muffins, or bagels with their high carbohydrate load. As I’ve ranted out about previously, the only yogurt available is Yoplait low fat , highly sugared-up yogurt which is arguably worse than starting the day with a candy bar.

A selection of breakfast cereals is available including Cheerios, Raisin Bran, and Frosted Flakes. Occasionally, when I have neglected to bring in my own yogurt, granola and/or fruit I will open up one of the Cheerios containers and consume a bowl mixed with 2% milk (full-fat, organic milk which I passionately advocate here and here is not available)

Pondering the Cheerios packaging and the cute little O’s made me wonder whether this highly processed and packaged food with a seemingly endless shelf life was truly a healthy choice.

The “ready-to-eat”  and allegedly heart-healthy cereal

Cheerios and Honey-nut cheerios were  the #4 and #1 breakfast cereals in the US in 2013, generating almost a billion dollars in sales. Both of these GM blockbusters undoubtedly have reached their popularity by heavily promoting the concept that they are heart healthy.

The Cheerios label is all about the heart. The little O’s sit in a heart-shaped bowl. A prominent red heart with a check inside it attests to the AHA having certified Cheerios as part of its checkmark.heart.org program. Additional text states “low  in Saturated fat and cholesterol” and “diets low in saturated fat and cholesterol may reduce the risk of heart disease.”

For those concerned about GMO  the package also states “not made with genetically modified ingredients”

Is the Fiber in Cheerios “heart-healthy” ?

Beta-glucan is a soluble fiber primarily located in the endosperm cell wall of oats. Early studies showed that oats and beta-glucan soluble fiber could reduce total and LDL (bad cholesterol) levels. The mechanism isn’t really known. (see the end of post for possible mechanisms). The Quaker oats web site oversimplifies the mechanism thusly :

“In your digestive tract, it acts as a sponge, soaking up cholesterol and carrying it out of the body”

This narrative fits with the oversimplified and now discredited descriptions of atherosclerosis which attribute it directly to consumption of cholesterol and fatty acids. See here if you’d like to appreciate how complex the process truly is.

The FDA sanctions oats as heart healthy

In 1997, the FDA reviewed 33 studies (21 showing benefit and 12 not) and decided to allow a health claim for foods that contain oats and soluble fiber. A minimum dose of 3 grams/day of oat beta-glucan was suggested for a beneficial reduction in blood cholesterol and (presumably, although never documented) a subsequent decline in coronary heart disease.

In 1998 Johnson, et al, published the results of a study funded by a grant from General Mills that showed that  inclusion of whole grain oat ready to eat cereal providing 3 grams of beta-glucan as part of a low fat diet reduced  LDL cholesterol by 4% after 6 weeks. HDL was unchanged. Patients in this study consumed 45 grams (1.5 oz) of cheerios at breakfast and then again in the evening. There was a total of 3 grams of soluble fibre in this amount of Cheerios. A control group consumed corn flakes in a similar fashion without change in LDL.

General Mills took this weak data and ran with it and began posting on Cheerios the following statements

 “Did you know that in just 6 weeks Cheerios can reduce bad cholesterol by an average of 4 percent? Cheerios is … clinically proven to lower cholesterol. A clinical study showed that eating two 1 1/2 cup servings daily of Cheerios cereal reduced bad cholesterol when eaten as part of a diet low in saturated fat and cholesterol.”

Although the FDA had approved verbiage indicating oats may reduce heart disease “when eaten as part of a diet low in saturated fat and cholesterol” the agency objected to General Mills claiming that Cheerios lowers cholesterol “when eaten as part of a diet low in saturated fat and cholesterol”.

The FDA  issued a warning letter to General Mills in 2009 in which the agency alleged “serious violations” of the FDC Act in the label and labeling of Cheerios cereal.

Based on claims made on your product’s label, we have determined that your Cheerios® Toasted Whole Grain Oat Cereal is promoted for conditions that cause it to be a drug because the product is intended for use in the prevention, mitigation, and treatment of disease.

Should We Be Treating High Cholesterol or Preventing Heart Disease?

The FDA was telling General Mills that it was OK to say that Cheerios may reduce heart disease but not that it can reduce cholesterol because that made it a drug. It makes no sense.

The only thing that had been demonstrated for oat soluble fiber and Cheerios in particular was a reduction in cholesterol. There has never been a study with oats showing a reduction in heart disease..

It’s the heart disease, the atherosclerosis clogging our arteries and causing heart attacks and strokes that we want to prevent. We could care less about lowering cholesterol if it doesn’t prevent atherosclerosis.

A recent review of studies since the FDA ruling shows that 70% of studies show some reduction in LDL with beta-glucan. Interstingly, the studies which added beta-glucan to liquids were generally positive whereas addition to solids such as muffins usually did not show benefit.

I’m going to accept as evidence-based the claim that whole oats can lower your LDL about 7% if you consume a very large amount of them on a daily basis.

However, the critical question for any drug or dietary intervention is does it prevent atherosclerosis, the root cause of heart attacks and strokes. There has been in the past an assumption that lowering cholesterol by any means would result in lowering of atherosclerosis. This theory has been disproven by recent studies showing that ezetimibe and niacin which significantly lower LDL do not reduce surrogate markers of atherosclerosis or cardiovascular events any more than placebo when added on to statin drugs. The recently revised cholesterol guidelines endorse the concept of treating risk of atherosclerosis rather than cholesterol levels.

Eat Real Foods, Mostly Plants, Not Too Much

If you follow Michael Pollan’s simple dictum you will get plenty of fiber, soluble or otherwise and you will avoid the necessity to obsess over the macronutrients in your diet, fiber or otherwise. Throw in some cheerios and oatmeal every once in a while if you like them, in their unadulterated state they are a healthy food choice.

To quote David Katz

Wholesome foods in sensible combinations, as prevail in the world’s Blue Zones, seemingly take care of all nutrients, by focusing on none. Such dietary patterns can be low in fat, as vegan and traditional Asian diets tend to be; or high in fat, as Mediterranean diets tend to be. Variations on a common theme nicely accommodate personal preference, allowing us all to find a dietary pattern to love that loves our health back.

Addendum

As promised, for those with inquiring minds and oatmeal-induced fortitude, I present from a recent review of fiber some discussion of proposed mechanisms of cholesterol lowering

The mechanism by which fiber lowers blood cholesterol remains undefined. Evidence suggests that some soluble fibers bind bile acids or cholesterol during the intraluminal formation of micelles. The resulting reduction in the cholesterol content of liver cells leads to an up-regulation of the LDL receptors and thus increased clearance of LDL cholesterol. However, increased bile acid excretion may not be sufficient to account for the observed cholesterol reduction. Other suggested mechanisms include inhibition of hepatic fatty acid synthesis by products of fermentation (production of short-chain fatty acids such as acetate, butyrate, propionate) ; changes in intestinal motility; fibers with high viscosity causing slowed absorption of macronutrients, leading to increased insulin sensitivity; and increased satiety, leading to lower overall energy intake.

and their take on soluble fibers overall importance

The modest reductions in cholesterol expected from intakes of soluble fiber within practical ranges may exert only a small effect on the risk of heart disease. For example, daily intake of 3 g soluble fiber from either 3 apples or 3 bowls (28-g servings) of oatmeal can decrease total cholesterol by ≈0.129 mmol/L (5 mg/dL), a ≈2% reduction. On the basis of estimates from clinical studies of cholesterol treatment,, this could lower the incidence of coronary artery disease by ≈4%.

and a comment on publication bias: the finding that studies that do not show a positive effect of the intervention tend not to get published.

Publication bias toward studies that showed positive results is always a potential issue in meta-analyses and could be operating in this study. If this were true, then the small effect estimates associated with intake of dietary soluble fiber would be further attenuated, further highlighting the need for conservative public health claims. The major benefit from eating fiber-rich foods may be a change in dietary pattern, resulting in a diet that is lower in saturated and trans-unsaturated fats and cholesterol and higher in protective nutrients such as unsaturated fatty acids, minerals, folate, and antioxidant vitamins.

 

Tofu: Heart Healthy SuperFood or Environmental Nightmare?

Most of my patients think tofu and soy protein are particularly heart healthy food choices. Since tofu contains significant calcium and protein, it is often viewed as a healthier alternative to dairy (which has inappropriately been labeled as heart unhealthy).

A huge growth in the use of soy protein occurred between 1996 and 2009 with annual sales of foods containing soy expanding from $1 billion to $4.5 billion. This appears to have been driven by a perception that soy is more healthful than other sources of protein (especially animal protein).

Much of the success of soy foods followed a 1999 decision by the FDA which approved a food-labeling health claim for soy protein for the prevention of coronary heart disease (CHD):

25 grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.

 Does soy deserve this designation? Should we be purposefully trying to consume more soy to lower our risk of heart disease?

Early studies, which compared consumption of 25 grams of soy protein versus control protein consumption, suggested a slight reduction in total and bad cholesterol levels. The problem with these studies is that a flawed surrogate marker (cholesterol or bad cholesterol) is being studied in place of the real disease (atherosclerosis and its associated complications, including heart attack and stroke). We now know that dietary interventions or drug therapies that lower cholesterol don’t necessarily reduce heart attacks or prolong life.

In 2000, the AHA published a document supporting the concept that 50 grams of soy protein per day would reduce heart disease risk .

However the AHA reversed this recommendation in a 2006 publication finding that

 In the majority of 22 randomized trials, isolated soy protein with isoflavones, as compared with milk or other proteins, decreased LDL cholesterol concentrations; the average effect was approximately 3%. This reduction is very small relative to the large amount of soy protein tested in these studies, averaging 50 g, about half the usual total daily protein intake. No significant effects on HDL cholesterol, triglycerides, lipoprotein(a), or blood pressure were evident. Among 19 studies of soy isoflavones, the average effect on LDL cholesterol and other lipid risk factors was nil. Soy protein and isoflavones have not been shown to lessen vasomotor symptoms of menopause, and results are mixed with regard to soy’s ability to slow postmenopausal bone loss. The efficacy and safety of soy isoflavones for preventing or treating cancer of the breast, endometrium, and prostate are not established; evidence from clinical trials is meager and cautionary with regard to a possible adverse effect. For this reason, use of isoflavone supplements in food or pills is not recommended. Thus, earlier research indicating that soy protein has clinically important favorable effects as compared with other proteins has not been confirmed. 

There is no scientific evidence that consuming soy protein lowers your risk of heart disease. There is no evidence that substituting soy protein for animal protein lowers your risk of heart disease. Certainly, if you like tofu (does anyone really like tofu?) and/or you have a philosophical desire to avoid meat and dairy consumption, tofu can provide a lot of the protein and calcium that you cannot get from eating only vegetables.

What does the searching the Internet tell us about tofu?

A Google search on the health benefits of tofu reveals stridently negative and positive (allegedly  evidence-based) articles (as is typical for everything in the world of nutrition). Medical News Today (“a leading health care internet publishing company,” which gets 9,000,00 views a month for unknown reasons), for example, has an overwhelmingly positive article written by a dietician which claims:

Countless studies have suggested that increasing consumption of plant-based foods like tofu, decreases the risk of obesity and overall mortality, diabetes, and heart disease and promotes a healthy complexion and hair, increased energy, and overall lower weight

The “Foundation for Integrative Medicine” (when you see the word “integrative” before the word “medicine,” substitute “unproven” and move to another website. This is a marker for quackery) cites similar claims, adding that regular tofu consumption reduces breast and lung cancer and osteoporosis.

None of these claims are supported in the medical literature.

On the anti-tofu side, we have this blog post from a chiropractor (chiropractors are usually big advocates of “integrative” medicine) who finds unfermented soy consumption to be the cause of myriad health problems including:

  • Breast Cancer
  • Brain damage
  • Infant abnormalities
  • Thyroid disorders
  • Kidney stones
  • Immune system impairment
  • Severe, and potentially fatal food allergies
  • Impaired fertility
  • Danger during pregnancy and nursing

None of these claims are supported by the medical literature

You can also read about why soy “May be a health risk and environmental Nightmare” here. The majority of soy grown in the US comes from genetically modified plants from Monsanto which have had a gene inserted that allows them to resist Roundup. Consequently, farmers can spray all the Roundup they want on the plants.

Nobody knows if this is a health risk or not. Monsanto likes to make the case that the overall effects of RoundupReady soy, as they like to call it, are positive, whereas Mother Jones writes that soy is “Scarier Than You Think”.

My bottom line recommendation on soy is that, like all other foods, we should try to consume it in its least industrially processed form as part of a balanced diet of real foods.

There is no scientifically proven reason to  avoid it or seek it out.