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.


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

14 responses to “Whole Grains Reduce Heart Attacks and Strokes

  1. You write: “since diabetics are prone to develop cardiovascular disease and whole grains could counteract that.”

    It doesn’t follow. The epidemiological studies weren’t done in diabetics. The positive contribution of whole grains has been ascribed to magnesium by many including Willett. Most diabetics are depleted and would benefit from a magensium supplement.

    Two parameters likely predict healthful outcomes for diabetics: an HbA1c less than 6% (UKPDS etc), and a ratio of triglycerides to HDL-cholesterol of less than 3, per G Reaven http://jcem.endojournals.org/cgi/reprint/86/8/3574. If these parameters are out of control, adding grains in any form will worsen them.

    I’m insulin-dependent, and my HbA1c is 5.5% and my TG/HDL is 1.7. When grains were only 15% of my diet, the best I could do was 7.5% and 4.6 even with fanatic devotion to exercise and 7 blood tests per day. I had hypoglycemic epsiodes frequently one bad enough for the emergency room. No grains, no hypoglycemic episondes, nary a one in 12 years.

    Diabetics are almost all carbohydrate cravers. Encouraging any who are sufficiently low-carb to have decent HbA1c and TG/HDL is not in their best interests. I implore you to talk this over with Dr Richard Bernstein (914) 698-2058, for he has trodden this path before you both personally and professionally.

    It’s deseprately hard for a diabetic to go against this sort of well-meaning advice, and to the extent to which they are persuaded, their lives are shortened. Make the experiment on your diabetic patients, with their permission, by all means – but don’t advocate to the diabetic public increased carbs based on flimsy epidemiological data when cutting-edge clinical research in human diabetics shows decreasing carbs certainly protects against complications and likely against the threat of degenerative disease via lowered TG/HDL – see Gannon & Nuttall http://diabetes.diabetesjournals.org/content/53/9/2375.long

    • Hi, Jonathan.

      When I wrote “…since diabetics are prone to develop cardiovascular disease and whole grains could counteract that…”, perhaps I should have stressed “could,” meaning perhaps or maybe. I don’t think we know if they WOULD. The study in diabetics hasn’t been done.

      For a diabetic eating 20-30 grams of carb daily but wanting to try more, whole grains are not my first recommendation. In fact they are my last, following fruits (lower-carb versions first), more vegetables (lower-carb varieties first), legumes, and milk products (lower-carb varieties first).

      I’m assuming there are at least some type 2 diabetics who could eat 1-2 servings of whole grains daily without undue spikes in blood sugar, and without requiring higher doses or additional diabetic drugs that have unknown long-term side effects. Maybe I’m wrong.

      I have a huge degree of respect for Dr. Bernstein. If I had type 1 diabetes, I might well follow his eating plan. [I bet only one out of a hundred physicians would say that.] I’ve read his “Diabetes Solution” book. As I recall, he’s anti-grain.


  2. 2.5 servings of whole grain isn’t very much considering the food pyramid recommends 6-10 servings of grains a day. I wonder how the ratio of whole grain to total grains consumed factors in.

  3. Please look at G Reaven http://jcem.endojournals.org/cgi/reprint/86/8/3574. It answers your questions. TG/HDL is proportional to daylong insulin exposure, so that your diabetic patients with a low ratio are the ones who may be able to eat more carbs. Those with a high ratio, on the other hand, would be well-advised to eat less carbs. Reaven found that in otherwise-healthy individuals, a ratio over 3 was assoicated with a 36% chance of developing cancer, CVD, CVA or hypertension over the 6 years of follow-up. But the truly striking outcome was that no one with a ratio of less than 1.5 developed a degenerative disease. If you’re going to toss your hat in this ring, you should be fully informed.

    • “If you’re going to toss your hat in this ring, you should be fully informed.”

      That’s a bit of a flippant comment and I’m not sure if it’s directed at me or Steve. Either way, I think it’s not the least bit conducive to the debate as neither of us are exactly idiots. To call an epidemiological study pointless but refer to a study using only ~200 patients looking at hard cardiovascular endpoints as cutting edge is foolhardy. It may be hypothesis generating but by no means would I change ship based on 200 patients. We have no idea how that would apply to a larger heterogenous population. There’s a reason that CV trials are so large and expansive.

      I think Steve hit the nail on the head when he said we need a randomized, PROSPECTIVE trial. And we need to stop basing everything on biomarkers and start relying on hard endpoints. I would’ve hoped we’d learned our lesson from trials like ACCORD, ARBITER-6 HALT, etc where too much emphasis is placed upon markers. Diseases are soooo much more than the sum total of a few different molecules found in the blood.

      So yes, low carb/high protein can lower A1c but we still don’t know what that means to either micro or macrovascular disease. I’m not saying it won’t work. It’s just that the jury is still out on it. Given our current state of ignorance, the only dietary patterns that lower disease with good clinical evidence are the mediterranean diet or gastric surgery where fewer calories are consumed overall. Everything else is still theory.

  4. Isaac, I don’t know who you are but you sure are touchy. I wouldn’t dream of calling you an idiot unless you suggested I eat carbohydrates – I’m a 25-year insulin dependent diabetic, low-carb for 12 years, calcium score of zero and IMT carotid normal, no complications – my diabetologists shared your notion of the goodness of carbohydrates and until I went against them, my HbA1c was 7.5% – the UKPDS established that complications are far more likely at this level than at my current level of 5.5%. So low-carb works for me, but my comtempories at diagnosis who stayed low-fat all have severe complications including salami amputations, blindness and kidney failure. It may be that n=1 for this trial, but anecdotal evidence can be quite compelling if you’re the 1. The data may be scant, but what there is of it suggests carbohydrates do not belong in the diabetic diet – Gannon & Nuttall http://diabetes.diabetesjournals.org/content/53/9/2375.long and the UKPDS (a masive propsective trial, by the way) suggests at the very least diabetic complications can be avoided because avoiding carbohydrates normalizes HbA1c.

    • I’m not suggesting eating carbs for diabetics, especially the western version of carbs. On the contrary, I think the low fat diet is an utter disaster and I commend you for being able to disagree with your doc and follow through what works for you (far too many people blindly follow their doctors to their own detriment) but I think the science is far from settled. My question for diabetics is what is the most beneficial macronutrient to replace the carbs with and in what amounts (I don’t know that all fats or proteins are created equal)? I’m not convinced that animal protein and fat is the better option. We don’t yet know what the high protein load does to renal function long term but nor am I convinced that vegetarian is superior either. Then there is the whole saturated vs unsaturated, omega 6 vs omega 3, etc for fat. My suspicion is that total caloric load is the more critical variable and with a higher fat/protein content, it tends to be more self limiting whereas one is almost guaranteed to overeat on carbs, especially refined.

      And I also suspect that type I and type II have some differences with respect to comorbidities. While it’s clear, as you said, that reduction in A1c reduces complications in type I, that is not nearly as clear in type II across all methodologies. The how seems to be as important as the the end goal. It does not appear that the end justifies the means in A1c reduction. I wish lap band was investigated more seriously because it offers meaningful long term reductions in the disease.

  5. Tks for the boost! I’m convinced refined vegetable oils kill so I eat sats, animal fat, egg yolks etc for about 68% of calories, fish 3x per wk and olive oil for salad dressings LDL=110 HDL=53 TGs=67 so far so good at 12 years. RFDs bring no vit E and add 2% trans – who needs that?

    EPIC-Norfolk found HbA1c “continuously related to subsequent all-cause, cardiovascular, and ischaemic heart disease mortality through the whole population distribution, with lowest rates in those with HbA(1c) concentrations below 5% … this effect remained (relative risk 1.46, P=0.05 adjusted for age and [blood pressure, cholesterol, BMI and smoking]) after men with known diabetes, an HbA(1c) concentration >/=7%, or history of myocardial infarction or stroke were excluded” (Khaw 2004)

    Seems likely that lowering HbA1c by removing carbs helps, but adding drugs without removing the carbs (ACCORD etc) kills diabetics faster.

    • “Seems likely that lowering HbA1c by removing carbs helps, but adding drugs without removing the carbs (ACCORD etc) kills diabetics faster.”

      We know people with lower A1c do better epidemiologically but we do not yet know the most effective way to lower A1c interventionally. If a type II, bmi of >35, hypertensive, hyperlipidemic, etc came to me, I wouldn’t be nearly as concerned about their carb intake and A1c as I would be about A) getting them on an antihypertensive and antihyperlipidemic ASAP and B) getting them to lose weight in a sustainable fashion. It isn’t clear to me that long term (key word being long) weight loss is favored by low carb diets. They plateau just like everyone else. In fact, the best predictor of success seems to be sticking with whatever behavioral modification one uses, not necessarily which diet is used. And even then, the weight loss ain’t that impressive when compared to bariatric surgery. So to me, it all depends on the patient and what works for them.

      • I’m not sure you’re on the right track here since there but for the grace of god go I.

        Such people have hyperinsulinemia following carb intake, so why not skip the carbs and resolve that problem?

        The althernative low-fat, calorie-restricted diet ain’t going to work because they’ve been losing that battle since they got off the tit, otherwise they wouldn’t be in your office.

        Low-carb satiates, improves flow-mediated dilation, gets rid of small, dense LDL, lowers TGs and elevates HDL. I imagine you mention all this in your informed consent for treatment – unless you also juggle chainsaws for fun – and armed with the information, how many fatsos choose low-fat? Sure they’ll plateau like everybody else, but with lower insulin, improved flow-mediated dilation, fluffy LDL, lower TGs and higher HDL.

        Like that idiot Ancel Keys – can we agree he was an idiot? – said “People should know the facts, then if they want to eat themselves to death, let them.”

  6. Because lowering the carbs is not sufficient enough in most type II diabetics to resolve the disease. For example, see:


    ~10-12 pound weight loss and a less than 1 pt in A1c reduction just ain’t enough. Don’t get me wrong, it’s better than nothing, better than low fat, and in highly motivated patients, it can work (though long term I’m not convinced that it’s better than the med. diet). I’m just looking at the law of averages. Unfortunately, most patients aren’t so motivated as yourself. It’s just not the end all and be all. There’s no comparison to the data coming out with the gastric surgeries where ~80-90% of patients are no longer requiring diabetes meds at all. That’s clinically meaningful reduction in disease.

    I’ve yet to find an interventional dietary +/- pharmacological study where this kind of reduction in mortality (40% all cause, 56% for CAD, 60% for cancer and 92% for DIABETICS) is seen among the obese. That’s revolutionary therapy in my book and it also hints that it’s excess calories that are killing us.


    In your case, a type I and I’m assuming otherwise healthy individual, by all means, a low carb diet is the way to go. No arguments there. For a highly motivated type II, yes, try eliminating the carbs, eat ketogenic mediterranean, exercise, add weight loss meds if appropriate and see where it gets them. More power to them if they reach the healthy bmi, lose the metformin/TZDs and all the benefits (bp, lipids, A1c, etc) that go with it. But if they only lose 10 pounds and they need to lose 30-50, that’s not good enough. It’d be time to consider the big guns.

    • Isaac, I agree that bariatric surgery results for obese type 2 diabetics are impressive. Peri-operative mortality rates average roughly one in 200 (all comers, not just diabetics), so the surgery is usually considered a last resort, as you imply.

      I haven’t studied the issue enough to know if bariatric surgery cures type 2 diabetes or just puts it into remission. I read recently that a number of the bariatric diabetes “cures” are showing after-meal blood sugar elevations in the diabetic range while fasting sugars and hemoglobin A1c’s are near-normal, depending on how you define normal.


  7. Shai used “20 g of carbohydrates per day for the 2-month induction phase … with a gradual increase to a maximum of 120 g per day.” HbA1c drops 0.9%

    Compare O’Neall’s chart review of 30 diabetics (mixed types) on Bernstein’s 30g per day, http://tinyurl.com/2adk4gv, HbA1c ends at 5.7%. These outcomes are different as chalk and cheese.

    We diabetics get discouraged when prescribed diets don’t work, you don’t really know if they’ll adhere unless you give them an effective diet – study after study has shown this modified Atkins approach fails in diabetics (I think because diabetics are carb addicts, might as well offer an alcoholic a drink).

    If the Bernstein diet fails, then well thank heavens there’s bariatric surgery.

  8. pjnoir

    Grains- I live much better without them.
    High Fat- low carb no grains makes for a healthy heart and much improved metabolism