Category Archives: legumes

Experts Debate Composition of the Mediterranean Diet

…but they have some good ideas as to the healthy components, according to a report in MedPageToday. A sample:

Through a subtractive statistical technique, the EPIC investigators calculated that the biggest chunk of the health advantage—24%—came from moderate alcohol consumption (predominantly wine).

The other relative contributions were:

  • 17% from low consumption of meat and meat products
  • 16% from high vegetable consumption
  • 11% from high fruit and nut consumption
  • 11% from high monounsaturated-to-saturated lipid ratio (largely due to olive oil consumption)
  • 10% from high legume consumption

Here’s my definition of the Mediterranean diet.

Steve Parker, M.D.

Reference:
Sofi F, et al “Ideal consumption for each food group composing Mediterranean diet score for preventing total and cardiovascular mortality” EuroPRevent 2013; Abstract P106.

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Filed under Alcohol, Fruits, legumes, Mediterranean Diet, nuts, olive oil, Vegetables

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

Longevity Components of the Mediterranean Diet

According to Greek researchers, the components of the Mediterranean diet that contribute to longer lifespan are:

  • moderate alcohol consumption
  • low consumption of meat
  • high consumption of vegetables, fruits, nuts, olive oil, and legumes

The following didn’t seem to contribute much, if any:

  • cereals (the grain of a grass such as wheat, corn, oats)
  • dairy products
  • fish and seafood

Investigators at the University of Athens examined the Greek portion of the European Prospective Investigation into Cancer (EPIC) and Nutrition, which included 23,349 men and women free of diabetes, cancer, and coronary heart disease at the outset.  Food habits were documented by questionnaire. 

The focus of this particular study was death rates over an average follow-up of 8.5 years.  Adherence to the traditional Mediterranean diet ranged from minimal to high, as would be expected. 

As with numerous other studies of the Mediterranean diet, higher adherence to the Mediterranean diet was associated with lower chance of death. 

My Comments

The lack of benefit from fish is unexpected.  I have no explanation.  A preponderance of evidence elsewhere suggests fish consumption helps prolong life via lowered rates of heart disease.

Alcohol can be dangerous, of course.  Some people should not partake, ever.     

For people with diabetes who wish to avoid the carbohydrate load in cereals and dairy products, you don’t need to worry much about cutting those out of an otherwise Mediterranean-style diet.

Steve Parker, M.D. 

Reference:  Trichopoulou, Antonia, et al.  Anatomy of health effects of the Mediterranean diet: Greek EPIC prospective cohort studyBritish Medical Journal, 338 (2009): b2337.  DOI: 10.1136/bmj.b2337.

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Filed under Alcohol, Dairy Products, Fish, Fruits, Grains, Health Benefits, legumes, Mediterranean Diet, nuts, olive oil, Vegetables

Vinegar to Treat Diabetes?

Vinegar reduces blood sugar elevations after meals containing complex carbohydrates, according to the Department of Nutrition at Arizona State University.

Meals containing carbohydrates (and to a lesser extent, proteins) raise blood sugar after meals in people with or without diabetes.  [I’ve written previously about the normal ranges of blood sugars.]  Previous studies established that a single vinegar dose around mealtime lowers postprandial (after meal) blood sugar levels by up to 50%.  Arizona investigators wanted to know the best dose and timing for reducing postprandial blood sugar elevations.

They ran multiple tests on about 40 adults who reported they were generally healthy except nine had type 2 diabetes (not taking insulin). 

Findings

Mealtime vinegar ingestion reduced postprandial (two hours after meal)  blood sugars by about 20% compared to placebo.  The test meal was white bagel (variable amounts), 20 g of butter, and 200 g of juice. 

The most effective dose of vinegar was 10 g (about two teaspoons or 10 ml) of 5% acetic acid vinegar (either Heinz apple cider vinegar or Star Fine Foods raspberry vinegar).  This equates to two tablespoons of vinaigrette dressing (two parts oil/1 part vinegar) as might be used on a salad.  The authors also say that “…two teaspoons of vinegar could be consumed palatably in hot tea with lemon at mealtime.”

Discussion

The study authors suggest that the blood-sugar-lowering effect of vinegar may be related to inhibition of digestive enzymes or to a slower rate of empyting by the stomach.  Remember that most of digestion and absorption of nutrients occurs in the small intestine; the stomach first has to empty food into the small intestine.  Vinegar seems to inhibit digestion of starch but not of simple (monosaccharide) sugars.

They also note another study that found vinegar slowed the rate of stomach emptying by almost 40% in type 1 diabetics with gastoparesis, potentially raising the risk of low blood sugar.

Take-Home Points

The development of cardiovascular disease, like heart attacks and strokes, seems to be tied especially to elevations of blood sugar after meals as compared to before-meal or fasting sugar levels.  This may be related to formation of free radicals  and inflammatory mediators.  So reduction of postprandial blood sugar elevations by vinegar may be particularly helpful in preventing heart disease.  It will be many years before we can prove this by a clinical study, if ever. 

Diabetics, especially type 2’s without gastroparesis, may better tolerate grains, fruits, and legumes—in terms of lower blood sugar spikes—if they eat them in a meal that includes two teaspoons of vinegar. 

Steve Parker, M.D.

Reference:  Johnston, Carol, et al.  Examination of the antiglycemic properties of vinegar in healthy adults.  Annals of Nutrition and Metabolism, 56 (2010): 74-79.

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Filed under Drugs for Diabetes, Fruits, Grains, legumes

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

Eat the Right Carbs to Alleviate Diabetes and Heart Disease

Harvard’s Dr. Frank Hu in 2007 called for a paradigm shift in dietary prevention of heart disease, de-emphasizing the original diet-heart hypothesis and noting instead that “. . . reducing dietary GL [glycemic load] should be made a top public health priority.”  Jim Mann at the University of Otago (Dunedin, New Zealand) authored a 2007 review of carbohydrates and effects on heart disease and diabetes.  Here are highlights from the article summary in the European Journal of Clinical Nutrition:

The nature of carbohydrate is of considerable importance when recommending diets intended to reduce the risk of type II diabetes and cardiovascular disease and in the treatment of patients who already have established diseases. Intact fruits, vegetables, legumes and whole grains are the most appropriate sources of carbohydrate. Most are rich in [fiber] and other potentially cardioprotective components.  Many of these foods, especially those that are high in dietary fibre, will reduce total and low-density lipoprotein cholesterol and help to improve glycaemic control in those with diabetes.

Frequent consumption of low glycaemic index foods has been reported to confer similar benefits, but it is not clear whether such benefits are independent of the dietary fibre content of these foods or the fact that low glycaemic index foods tend to have intact plant cell walls.

A wide range of carbohydrate intake is acceptable, provided the nature of carbohydrate is appropriate. Failure to emphasize the need for carbohydrate to be derived principally from whole grain cereals, fruits, vegetables and legumes may result in increased lipoprotein-mediated risk of cardiovascular disease, especially in overweight and obese individuals who are insulin resistant.

Why does this matter to me and readers of this blog?  Dietary carbohydrates are a major determinant of blood sugar levels, tending to elevate them.  Chronically high blood sugar levels are associated with increased complication rates from diabetes.  People with diabetes are prone to develop heart disease, namely coronary artery disease, which causes heart attacks, weakness of the heart muscle, and premature death. 

Steve Parker, M.D.

References: 

Mann, J.  Dietary carbohydrate: relationship to cardiovascular disease and disorders of carbohydrate metabolismEuropean Journal of Clinical Nutrition, 61 (2007): Supplement 1: S100-11.

Hu, Frank.  Diet and cardiovascular disease prevention: The need for a paradigm shift.  Journal of the American College of Cardiology, 50 (2007): 22-24.

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Filed under Carbohydrate, coronary heart disease, Fiber, Fruits, Glycemic Index and Load, Grains, legumes, Vegetables

Does Diet Influence Risk of Stroke?

Harvard researchers suggest that our food consumption does indeed influence our risk of suffering a stroke.  This matters since stroke is the third leading cause of death in the U.S.

Scientists looked carefully at 121 different studies—published between 1979 and 2004—on the relationship between dietary factors and stroke.  High blood pressure is a major modifiable risk factor for stroke, so it also was considered.  Dietary factors included fats, minerals, animal protein, cholesterol, fish, whole grains, fiber, carbohydrate quality, fruits and vegetables, antioxidants, B vitamins, and dietary patterns.

I quote their conclusions:

Diets low in sodium and high in potassium lower blood pressure which will likely reduce stroke risk.

Consumption of fruits and vegetables, whole grains, folate, and fatty fish are each likely to reduce stroke risk.

A prudent or traditional Mediterranean dietary pattern, which incorporates these individual dietary components as well as intake of legumes and olive oil, may also prevent stroke.

Evidence is limited or inconsistent regarding optimal levels of dietary magnesium, calcium, antioxidants, total fat, other fat subtypes, cholesterol, carbohydrate quality, or animal protein for stroke prevention.

A diet low in sodium, high in potassium, and rich in fruits, vegetables, whole grains, cereal fiber, and fatty fish will likely reduce the incidence of stroke.

Take Home Points

The article abstract does not address the optimal intake amount of these various foods, vitamins, and minerals.  That’s probably not known with any certainty.

The traditional Mediterranean diet incorporates many of these stroke-preventing foods.  The Advanced Mediterranean Diet helps people lose weight while teaching how to eat Mediterranean-style.

The very low-carb Ketogenic Mediterranean Diet includes these stroke-preventing foods and minerals, except for whole grains and a tendency to be low in potassium.  The KMD is high in total fat and animal protien, and potentially high in cholesterol; this study indicates those issues are nothing to worry about in terms of future strokes.

I’ll use articles such as this to recommend long-term food consumption for followers of any future Diabetic Mediterranean Diet.

Steve Parker, M.D.

Reference:  Ding, E.L, and Mozaffarian, D.  Optimal dietary habits for the prevention of stroke. Seminars in Neurology, 26 (2006): 11-23.

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Filed under Fish, Fruits, Grains, Health Benefits, legumes, Mediterranean Diet, olive oil, Stroke, Vegetables