Tag Archives: coronary heart disease

High-Carbohydrate Eating Promotes Heart Disease in Women

Women double their risk of developing coronary heart disease if they have high consumption of carbohydrates, according to research recently published in the Archives of Internal Medicine

Men’s hearts, however, didn’t seem to be affected by carb consumption. I mention this crucial difference because I see a growing trend to believe that “replacing saturated fat with carbohydrates is a major cause of heart disease.”  If true, it seems to apply only to women.

We’ve known for a while that high-glycemic-index eating was linked to heart disease in women but not menGlycemic index is a measure of how much effect a carbohydrate-containing food has on blood glucose levels.  High-glycemic-index foods raise blood sugar higher and for longer duration in the bloodstream.

High-glycemic-index foods include potatoes, white bread, and pasta, for example.

The study at hand includes over 47,000 Italians who were interrogated via questionnaire as to their food intake, then onset of coronary heart disease—the cause of heart attacks—was measured over the next eight years. 

Among the 32,500 women, 158 new cases of coronary heart disease were found.

ResearchBlogging.orgResearchers doing this sort of study typically compare the people eating the least carbs with those eating the most.  The highest quartile of carb consumers and glycemic load had twice the rate of heart disease compared to the lowest quartile. 

The Cleave-Yudkin theory of the mid-20th century proposed that excessive amounts of refined carbohydrates cause heart disease and certain other chronic systemic diseases.  Gary Taubes has also written extensively about this.  Theresearch results at hand support that theory in women, but not in men. 

Practical Applications

Do these research results apply to non-Italian women and men?  Probably to some, but not all.  More research is needed.

Women with a family history coronary heart disease—or other CHD risk factors—might be well-advised to put a limit on total carbs, high-glycemic-index foods, and glycemic load.  I’d stay out of that “highest quartile.”  Don’t forget: heart disease is the No. 1 killer of women.

See NutritionData’s Glycemic Index page for information you can apply today.

Steve Parker, M.D.

Disclaimer:  All matters regarding your health require supervision by a personal physician or other appropriate health professional familiar with your current health status.  Always consult your personal physician before making any dietary or exercise changes.

References: Sieri, S., Krogh, V., Berrino, F., Evangelista, A., Agnoli, C., Brighenti, F., Pellegrini, N., Palli, D., Masala, G., Sacerdote, C., Veglia, F., Tumino, R., Frasca, G., Grioni, S., Pala, V., Mattiello, A., Chiodini, P., & Panico, S. (2010). Dietary Glycemic Load and Index and Risk of Coronary Heart Disease in a Large Italian Cohort: The EPICOR Study Archives of Internal Medicine, 170 (7), 640-647 DOI: 10.1001/archinternmed.2010.15

Barclay, Alan, et al.  Glycemic index, glycemic load, and chronic disease risk – a meta-analysis of observational studies [of mostly women].  American Journal of Clinical Nutrition, 87 (2008): 627-637.

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Filed under Carbohydrate, coronary heart disease, Glycemic Index and Load

Diabetes and Shortened Lifespan: “How Bad Is It, Doc?”

Diabetes mellitus for years has been linked with cardiovascular disease such as heart failure and coronary heart disease (blocked arteries in the heart, and the leading cause of death in the Western world).  How scared should diabetics be?

An article  in the Archives of Internal Medicine gives us one answer.

Researchers from the Netherlands and Harvard examined medical records of 5,209 people (mostly white, 64% men) enrolled in the Framingham (Massachusetts, USA) Heart Study.  This cohort has been examined every other year for more than 46 years. 

Study subjects who had diabetes at age 50 were identified; health outcomes going forward were then analyzed, with particular attention to lifespan and cardiovascular disease.  “Cardiovascular disease” in this context means coronary heart disease, stroke, congestive heart failure, intermittent claudication (leg pain during exertion caused by blocked arteries), and transient ischemic attack (stroke-like symptoms that resolve within 24 hours).

Results

Compared to those in the cohort free of diabetes, having diabetes at age 50 more than doubled the risk of developing cardiovascular disease for both women and men. 

Compared to those without diabetes, having both cardiovascular disease and diabetes approximately doubled the risk of dying, regardless of sex.

Compared to those without diabetes, women and men with diabetes at age 50 died 7 or 8 years earlier, on average.

[Specific causes of death were not reported.]

Take-Home Points

We’d likely see longer lifespans and less cardiovascular disease if we could prevent diabetes in the first place.  How do we do that?  Strategies include regular physical activity, avoidance or reversal of overweight and obesity, and low-glycemic-index diets.

The Mediterranean diet it linked to reduced heart attacks and strokes, and longer lifespan.  That’s why I’ve been working for the last year and a half to adapt it for diabetics.

ResearchBlogging.orgWe have better treatments for cardiovascular disease and diabetes and these days, so the death rates and illness numbers shouldn’t  be quite so alarming.  Up-to-date management of diabetes and cardiovascular disease will prevent some acute disease events—such as heart attacks and strokes—and prolong life.   

Steve Parker, M.D.

References: 

Franco, O., Steyerberg, E., Hu, F., Mackenbach, J., & Nusselder, W. (2007). Associations of Diabetes Mellitus With Total Life Expectancy and Life Expectancy With and Without Cardiovascular Disease Archives of Internal Medicine, 167 (11), 1145-1151 DOI: 10.1001/archinte.167.11.1145

Knowler, W.C., et al.  Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin.  New England Journal of Medicine, 346 (2002): 393-403.

Tuomilehto, J., et al.  Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance.  New England Journal of Medicine, 344 (2001): 1,343-1,350.

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Filed under coronary heart disease, Diabetes Complications, Stroke

Are Refined Carbs Worse for Your Heart Than Saturated Fat?

To reduce coronary heart disease, we need to focus on reducing consumption of refined carbohydrates rather than fat and cholesterol, according to Dr. Frank Hu.

Dr. Hu is not a wild-eyed, bomb-throwing radical. He’s a Harvard professor of nutrition and epidemiology with both M.D. and Ph.D. degrees.  High-glycemic-index carbs in particular are the bad boys, he writes in an editorial published in the American Journal of Clinical Nutrition earlier this year.

Additional details are at my April 26, 2010, post at the Self/NutritionData Heart Health Blog.

Steve Parker, M.D.

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Filed under Carbohydrate, coronary heart disease, Fat in Diet, Glycemic Index and Load

Whole Grains Reduce Heart Attacks and Strokes

Whole grain consumption is associated with a 21% reduction in cardiovascular disease when compared to minimal whole grain intake, according to a 2008 review article in Nutrition, Metabolism, and Cardiovascular Disease.   

Coronary heart disease is the No. 1 killer in the developed world.  Stroke is No. 3.  The term “cardiovascular disease” lumps together heart attacks, strokes, high blood pressure,  and generalized atherosclerosis (hardening of the arteries). 

Investigators at Wake Forest University reviewed seven pertinent studies looking at whole grains and cardiovascular disease.  The studies looked at groups of people, determining their baseline food consumption via questionnaire, and noted disease development over time.  These are called “prospective cohort studies.” 

None of these cohorts was composed purely of diabetics.

The people eating greater amounts of whole grain (average of 2.5 servings a day) had 21% lower risk of cardiovascular disease events compared to those who ate an average of 0.2 servings a day.  Disease events included heart disease, strokes, and fatal cardiovascular disease.  The lower risk was similar in degree whether the focus was on heart disease, stroke, or cardiovascular death.

Note that refined grain consumption was not associated with cardiovascular disease events. 

Why does this matter?

The traditional Mediterranean diet is rich in whole grains, which may help explain why the diet is associated with lower rates of cardiovascular disease.  If we look simply at longevity, however, a recent study found no benefit to the cereal grain component of the Mediterranean diet.  Go figure . . . doesn’t add up. 

Readers here know that over the last four months I’ve been reviewing the nutritional science literature that supports the disease-suppression claims for consumption of fruits, vegetables, and legumes.  I’ve been disappointed.  Fruit and vegetable consumption does not lower risk of cancer overall, nor does it prevent heart disease.  I haven’t found any strong evidence that legumes prevent or treat any disease, or have an effect on longevity.  Why all the literature review?  I’ve been deciding which healthy carbohydrates diabetics and prediabetics should add back into their diets after 8–12 weeks of the Ketogenic Mediterranean Diet.

The study at hand is fairly persuasive that whole grain consumption suppresses heart attacks and strokes and cardiovascular death.  [The paleo diet advocates and anti-gluten folks must be disappointed.]  I nominate whole grains as additional healthy carbs, perhaps the healthiest.

But . . .

. . .  for diabetics, there’s a fly in the ointment: the high carbohydrate content of grains often lead to high spikes in blood sugar.  It’s a pity, since diabetics are prone to develop cardiovascular disease and whole grains could counteract that.  We need a prospective cohort study of whole grain consumption in diabetics.  It’ll be done eventually, but I’m not holding my breath.

[Update June 12, 2010: The aforementioned study has been done in white women with type 2 diabetes.  Whole grain and bran consumption do seem to protect them against overall death and cardiovascular death.  The effect is not strong.]

What’s a guy or gal to do with this information now?

Non-diabetics:  Aim to incorporate two or three servings of whole grain daily into your diet if you want to lower your risk of heart disease and stroke. 

Diabetics:  Several options come to mind:

  1. Eat whatever you want and forget about it [not recommended].
  2. Does coronary heart disease runs in your family?  If so, try to incorporate one or two servings of whole grains daily, noting and addressing effects on your blood sugar one and two hours after consumption.  Eating whole grains alone will generally spike blood sugars higher than if you eat them with fats and protein.  Review acceptable blood sugar levels here.
  3. Regardless of family history, try to eat one or two servings of whole grains a day, noting and addressing effects on your blood sugar.  Then decide if it’s worth it.  Do you have to increase your diabetic drug dosages or add a new drug?  Are you tolerating the drugs?  Can you afford them?    
  4. Assess all your risk factors for developing heart disease: smoking, sedentary lifestyle, high blood pressure, age, high LDL cholesterol, family history, etc.  If you have multiple risk factors, see Option #3.  And modify the risk factors under your control.   
  5. Get your personal physician’s advice.    

Steve Parker, M.D.

Extra Credit:  The study authors suggest a number of reasons—and cite pertinent scientific references—how whole grains might reduce heart disease:

  • improved glucose homeostasis (protection against insulin resistance, less rise in blood sugar after ingestion [compared to refined grains], improved insulin sensitivity or beta-cell function)
  • advantageous blood lipid effects (soluble fiber from whole grains [especially oats] reduces LDL cholesterol, lower amounts of the small LDL particles thought to be particularly damaging to arteries, tendency to raise HDL cholesterol and trigylcerides [seen with insulin resistance in the metabolic syndrome])
  • improved function of the endothelial cells lining the arteries (improved vascular reactivity)

Disclaimer:  All matters regarding your health require supervision by a personal physician or other appropriate health professional familiar with your current health status.  Always consult your personal physician before making any dietary or exercise changes.

Reference: Mellen, P.B, Walsh, T.F., and Herrington, D.M.  Whole grain intake and cardiovascular disease: a meta-analysisNutrition, Metabolism and Cardiovascular Disease, 18 (2008): 283-290.

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Filed under Carbohydrate, coronary heart disease, Diabetes Complications, Grains, ketogenic diet, legumes, Mediterranean Diet, Stroke

Fruits and Vegetables DON’T Prevent Heart Disease

Fruit and vegetable consumption does not seem to reduce the risk of heart attacks (coronary heart disease), according to a recent literature review by French epidemiologists.

I recently wrote about a study that found no overall reduced risk of cancer via consumption of fruits and vegetables.

Heart attacks and cancer are the first and second leading causes of death in the developed world.

So just why, again, are we supposed to be eating our fruits and vegetables?

Here’s most of the abstract written by the epidemiologists:

This Review summarizes the evidence for a relationship between fruit and vegetable consumption and the occurrence of coronary heart disease…Most of the evidence supporting a cardioprotective effect comes from observational epidemiological studies; these studies have reported either weak or nonsignificant associations.  Controlled nutritional prevention trials are scarce and the existing data do not show any clear protective effects of fruit and vegetables on coronary heart disease.  Under rigorously controlled experimental conditions, fruit and vegetable consumption is associated with a decrease in blood pressure, which is an important cardiovascular risk factor.  However, the effects of fruit and vegetable consumption on plasma lipid levels, diabetes, and body weight have not yet been thoroughly explored.  Finally, the hypothesis that nutrients in fruit and vegetables have a protective role in reducing the formation of atherosclerotic plaques and preventing complications of atherosclerosis has not been tested in prevention trials.  Evidence that fruit and vegetable consumption reduces the risk of cardiovascular disease remains scarce thus far.

What do they mean by controlled prevention trials?  Here’s an example.  Find 20,000 people with similar characteristics.  Randomly assign half of them to eat significantly more fruits and vegetables, and make sure they do it.  The other half eats their usual way, and make sure they do it.  Analyze the entire group’s health and food consumption after 10 years and see which half has more or less heart disease.   

Such a study is very difficult and costly.  Even if the fruit and veggie group had less heart disease, someone would argue that the heart benefit was gained because of what they cut out of their eating to make way for the fruits and veggies!  “They quit eating Cheetos; that’s why they had fewer heart attacks.”

Bottom Line

Fruits and vegetables don’t prevent heart disease, according to these researchers.

Fruits and vegetables are components of overall healthy diet patterns such as the Mediterranean diet, the DASH diet, and the “prudent diet.”  Is it possible they reduce the risk of stroke, the second leading cause of death?  I’ll leave that for another day.

I’m starting to think if I read enough nutritional literature, I won’t know anything with certainty.

Steve Parker, M.D. 

Dauchet L., Amouyel, P., and Dallongeville, J. (via MedScape).  Fruits, vegetables and coronary heart disease.  Nature Reviews Cardiology, 6 (2009): 599-608.  doi: 1011038/nrcardio.2009.131

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Filed under coronary heart disease, Fruits, Vegetables

Grains and Legumes: Any Effect on Heart Disease and Stroke?

Several scientific studies published in the first five years of this century suggest that whole grain consumption protects agains coronary heart disease and possibly other types of cardiovascular disease, such as stroke. 

Note that researchers in this field, especially outside the U.S., use the term “cereal” to mean “a grass such as wheat, oats, or corn, the starchy grains of which are used as food.”  They also refer frequently to glycemic index and glycemic load, spelled “glycaemic” outside the U.S.  Most of the pertinent studies are observational (aka epidmiologic): groups of people were surveyed on food consumption, then rates of diseases were associated with various food types and amounts.  “Association” is not proof of causation. 

Here are highlights from a 2006 review article in the European Journal of Clinical Nutrition

The researchers concluded that a relationship between whole grain intake and coronary heart disease is seen with at least a 20% and perhaps a 40% reduction in risk for those who eat whole grain food habitually vs those who eat them rarely.

Whole grain products have strong antioxidant activity and contain phytoestrogens, but there is insufficient evidence to determine whether this is beneficial in coronary heart disease prevention.

Countering the positive evidence for whole grain and legume intake has been the Nurses Health Study in 2000 that showed women who were overweight or obese consuming a high glycaemic load (GL) diet doubled their relative risk of coronary heart disease compared with those consuming a low GL diet.

The intake of high GI carbohydrates (from both grain and non-grain sources) in large amounts is associatied with an increased risk of heart disease in overweight and obese women even when fiber intake is high but this requires further confirmation in normal-weight women.

Promotion of carbohydrate foods should befocused on whole grain cereals because these have proven to be associatied with health benefits.

Whether adding bran to refined carbohydrate foods can improve the situation is also not clear, and it was found that added bran lowered heart disease risk in men by 30%.

Recommendation:  Carbohydrate-rich foods should be whole grain and if theyare not, then the lowest GI product available should be consumed.

My Comments

This journal article focuses on whole grains rather than legumes, and promotes whole grains more than legumes.  For people with diabetes, this may be a bit of a problem since grains—whole or not—generally have a higher glycemic index than legumes, which may have adverse effects on blood sugar control.  Keep in mind that highly refined grain products, like white bread, have a higher glycemic index than whole grain versions.

Did you notice that the abstract doesn’t recommend a specific amount of whole grains for the general population?  My educated guess would be one or two servings a day. 

Grains are high in carbohydrate, so anyone on a low-carb diet may have to cut carbs elsewhere. 

Diabetes predisoses to development of coronary heart disease.  Whole grains seem to help prevent heart disease, yet may adversely affect glucose control, contributing to diabetic complications.  It’s a quandary.  “Caught between the horns of a dilemma,” you might say.  So, what should a diabetic do with this information in 2010, while we await additional research results?

Several options come to mind:

  1. Eat whatever you want and forget about it.
  2. Note whether coronary heart disease runs in your family.  If so, try to incorporate one or two servings of whole grains daily, noting and addressing effects on your blood sugar.
  3. Try to eat one or two servings of whole grains a day, noting and addressing effects on your blood sugar.  Then decide if it’s worth it.  Is there any effect?  Do you have to increase your diabetic drug dosages or add a new drug?  Are you tolerating the drugs?    
  4. Assess all your risk factors for developing heart disease: smoking, sedentary lifestyle, high blood pressure, age, high LDL cholesterol, family history, etc.  If you have multiple risk factors, see Option #3.  And modify the risk factors under your control.   
  5. Get your personal physician’s advice.    

Before you stress out over this, be aware that we don’t really know whether a diabetic who doesn’t eat grains will have a longer healthier life by starting a daily whole grain habit.  Maybe . . . maybe not.  The study hasn’t been done.    

Steve Parker, M.D.

References:

Flight, I. and Clifton, P.  Cereal grains and legumes in the prevention of coronary heart disease and stroke: a review of the literatureEuropean Journal of Clinical Nutrition, 60 (2006): 1,145-1,159.

Malik, V. and Hu, Frank.  Dietary prevention of atherosclerosis: go with whole grainsAmerican Journal of Clinical Nutrition, 85 (2007): 1,444-1,445.

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Filed under Carbohydrate, coronary heart disease, Diabetes Complications, Grains, legumes, Stroke

Nuts: The Healthy Snack

MPj04031620000[1]Nut consumption is strongly linked to reduced coronary heart disease, with less rigorous evidence for several other health benefits, according to a recent article in the American Journal of Clinical Nutrition.

This is why I’ve included nuts as integral components of the Ketogenic Mediterranean Diet and the Advanced Mediterranean Diet.

Regular nut consumption is associated with health benefits in observational studies of various populations, within which are people eating few nuts and others eating nuts frequently.  Health outcomes of the two groups are compared over time.  Frequent and long-term nut consumption is linked to:

  • reduced coronary heart disease (heart attacks, for example)
  • reduced risk of diabetes in women (in men, who knows?)
  • less gallstone disease in both sexes
  • lower body weight and lower risk of obesity and weight gain 

The heart-protective dose of nuts is three to five 1-ounce servings a week.

Steve Parker, M.D.

Reference:  Sabaté, Joan and Ang, Yen.  Nuts and health outcomes: New epidemiologic evidenceAmerican Journal of Clinical Nutrition, 89 (2009): 1,643S-1,648S.

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Filed under Health Benefits, Mediterranean Diet, Prevention of T2 Diabetes