Tag Archives: health benefits

Evidence In Favor of Healthfulness of Whole Grains

I bought a sack of potatoes the other day.  The advertising on the sack proclaimed   these potatoes as “Gluten-Free!”.  As if other potatoes have gluten (they don’t).

In these days of gluten-free this and gluten-free that, the health benefits of grains—especially wheat—are being questioned.

A 2008 review article in a scientific journal confirmed the association between high whole grain intake and reduced incidence of cardiovascular disease.  Heart disease and strokes (subsets of cardiovascular disease) are the first and fourth leading causes of death, respectively, in the U.S.

The article authors, Philip Mellen, Thomas Walsh, and David Herrington, reviewed the scientific literature on the subject and found seven pertinent published observational studies.  Study participants were divided into those with high average whole grain intake (2.5 servings per day) and those with low average intake (0.2 servings a day, or 1 serving every 5 days).  Compared with low intake, participants with high intake had 21% lower risk of cardiovascular disease events, such as heart disease, stroke, and death from cardiovascular disease.

Refined grain intake, such as standard white bread, was not associated with cardiovascular disease one way or the other.

The authors conclude, “There is a consistent, inverse association between dietary whole grains and incident cardiovascular disease…and clinicians should redouble efforts to incorporate clear messages on the beneficial effects of whole grains into public health and clinical practice endeavors.”

I’ll be the first to admit that observational studies don’t prove that whole grains reduce the risk of cardiovascular disease.  They identify an association that should lead to additional testing of the hypothesis.  I don’t see any proof on the foreseeable horizon.

If heart attacks and strokes ran in my blood lines (genes), I’d try to incorporate two or three daily servings of whole grain into my diet, assuming I had no good reasons to avoid grains.

That being said, I’m also convinced that many can live long health lives without grains.

Steve Parker, M.D.

References and resources:

Mellen, Philip, et al.  Whole grain intake and cardiovascular disease: A meta-analysis.  Nutrition, Metabolism & Cardiovascular Diseases, 18, (2008): 283-290.

The Whole Grains Council.  Learn more about the benefits of various whole grains and how to find whole grain products.  Many recipes here, plus links to hundreds of recipes at other websites.

Documented Health Benefits of the Mediterranean Diet

The enduring popularity of the Mediterranean diet is attributable to three things:



3.Health benefits

For our purposes today, I use “diet” to refer to the usual food and drink of a person, not a weight-loss program.


The scientist most responsible for the popularity of the diet, Ancel Keys, thought the heart-healthy aspects of the diet related to low saturated fat consumption.He also thought the lower blood cholesterol levels in Mediterranean populations (at least Italy and Greece) had something to do with it, too.Dietary saturated fat does tend to raise cholesterol levels.


Even if Keys was wrong about saturated fat and cholesterol levels being positively associated with heart disease, numerous studies (involving eight countries on three continents) strongly suggest that the Mediterranean diet is one of the healthiest around.See References below for the most recent studies.


Relatively strong evidence supports the Mediterranean diet’s association with:

increased lifespan

lower rates of cardiovascular disease such as heart attacks and strokes

lower rates of cancer (prostate, breast, uterus, colon)

lower rates of dementia

lower incidence of type 2 diabetes



Weaker supporting evidence links the Mediterranean diet with:

slowed progression of dementia

prevention of cutaneous melanoma

lower severity of type 2 diabetes, as judged by diabetic drug usage and fasting blood sugars

less risk of developing obesity

better blood pressure control in the elderly

improved weight loss and weight control in type 2 diabetics

improved control of asthma

reduced risk of developing diabetes after a heart attack

reduced risk of mild cognitive impairment

prolonged life of Alzheimer disease patients

lower rates and severity of chronic obstructive pulmonary disease

lower risk of gastric (stomach) cancer

less risk of macular degeneration

less Parkinsons disease

increased chance of pregnancy in women undergoing fertility treatment

reduced prevalence of metabolic syndrome (when supplemented with nuts)

lower incidence of asthma and allergy-like symptoms in children of women who followed the Mediterranean diet while pregnant

Did you notice that I used the word “association” in relating the Mediterranean diet to health outcomes?Association, of course, is not causation.


The way to prove that a particular diet is healthier is to take 20,000 similar young adults, randomize the individualsin an interventional study to eat one of two test diets for the next 60 years, monitoring them for the development of various diseases and death.Make sure they stay on the assigned test diet.Then you’d have an answer for that population and those two diets.Then you have to compare the winning diet to yet other diets.And a study done in Caucasians would not necessarily apply to Asians, Native Americans, Blacks, or Hispanics.


Now you begin to see why scientists tend to rely on observationalrather than interventional diet studies.


I became quite interested in nutrition around the turn of the century as my patients asked me for dietary advice to help them lose weight and control or prevent various diseases.At that time, the Atkins diet, Mediterranean diet, and Dr. Dean Ornish’s vegetarian program for heart patients were all prevalent.And you couldn’t pick three programs with more differences!So I had my work cut out for me.


After much scientific literature review, I find the Mediterranean diet to be the healthiest for the general population.People with particular medical problems or ethnicities may do better on another diet. People with diabetes or prediabetes are probably better off with a carbohydrate-restricted diet, such as the Low-Carb Mediterranean Diet.


Dan Buettner makes a good argument for plant-based diets in his longevity book, The Blue Zones.The Mediterranean diet qualifies as plant-based.


Steve Parker, M.D.


     Sofi, Francesco, et al. Accruing evidence about benefits of adherence to the Mediterranean diet on health: an updated systematic review and meta-analysis. American Journal of Clinical Nutrition, ePub ahead of print, September 1, 2010. doi: 10.3945/ajcn.2010.29673

     Buckland, Genevieve, et al. Adherence to a Mediterranean diet and risk of gastric adenocarcinoma within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort study. American Journal of Clinical Nutrition, December 9, 2009, epub ahead of print. doi: 10.3945/ajcn.2009.28209

     Fortes, C., et al. A protective effect of the Mediterraenan diet for cutaneous melanoma. International Journal of Epidmiology, 37 (2008): 1,018-1,029.

Sofi, Francesco, et al. Adherence to Mediterranean diet and health status: Meta-analysis. British Medical Journal, 337; a1344. Published online September 11, 2008. doi:10.1136/bmj.a1344

     Benetou, V., et al. Conformity to traditional Mediterranean diet and cancer incidence: the Greek EPIC cohort. British Journal of Cancer, 99 (2008): 191-195.

Mitrou, Panagiota N., et al. Mediterranean Dietary Pattern and Prediction of All-Cause Mortality in a US Population, Archives of Internal Medicine, 167 (2007): 2461-2468.

     Feart, Catherine, et al. Adherence to a Mediterranean diet, cognitive decline, and risk of dementia. Journal of the American Medical Association, 302 (2009): 638-648.

Scarmeas, Nikolaos, et al. Physical activity, diet, and risk of Alzheimer Disease. Journal of the American Medical Association, 302 (2009): 627-637.

     Scarmeas, Nikolaos, et al. Mediterranean Diet and Mild Cognitive Impairment. Archives of Neurology, 66 (2009): 216-225.

Scarmeas, N., et al. Mediterranean diet and Alzheimer disease mortality. Neurology, 69 (2007):1,084-1,093.

     Fung, Teresa, et al. Mediterranean diet and incidence of and mortality from coronary heart disease and stroke in women. Circulation, 119 (2009): 1,093-1,100.

Mente, Andrew, et al. A Systematic Review of the Evidence Supporting a Causal Link Between Dietary Factors and Coronary Heart Disease. Archives of Internal Medicine, 169 (2009): 659-669.

     Salas-Salvado, Jordi, et al. Effect of a Mediterranean Diet Supplemented With Nuts on Metabolic Syndrome Status: One-Year Results of the PREDIMED Randomized Trial. Archives of Internal Medicine, 168 (2008): 2,449-2,458.

     Mozaffarian, Dariush, et al. Incidence of new-onset diabetes and impaired fasting glucose in patients with recent myocardial infarction and the effect of clinical and lifestyle risk factors. Lancet, 370 (2007) 667-675.

     Esposito, Katherine, et al. Effects of a Mediterranean-style diet on the need for antihyperglycemic drug therapy in patients with newly diagnosed type 2 diabetes. Annals of Internal Medicine, 151 (2009): 306-314.

     Shai, Iris, et al. Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet. New England Journal of Medicine, 359 (2008): 229-241.

     Martinez-Gonzalez, M.A., et al. Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study. British Medical Journal, BMJ,doi:10.1136/bmj.39561.501007.BE (published online May 29, 2008).

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

     Barros, R., et al. Adherence to the Mediterranean diet and fresh fruit intake are associated with improved asthma control. Allergy, vol. 63 (2008): 917-923.

     Varraso, Raphaelle, et al. Prospective study of dietary patterns and chronic obstructive pulmonary disease among US men. Thorax, vol. 62, (2007): 786-791.

Is the Paleo Diet Just a Fad?

Stockholm Palace

The paleo diet—aka Stone Age, caveman, or hunter-gatherer diet—has been growing in popularity since 2009.  Do we have firm evidence that it’s a healthy way of eating?

Swedish investigators at Karolinska Institutet found diminished weight, body mass index, blood pressure, and waist circumference in 14 healthy medical students eating a paleo diet for three weeks.

Published in 2008, this seems to be one of the seminal scientific studies of the paleo diet in modern Europeans.

Their version of the paleo diet:

  • Allowed ad lib: All fresh or frozen fruits, berries and vegetables except legumes, canned tomatoes w/o additives, fresh or frozen unsalted fish and seafood, fresh or frozen unsalted lean meats and minced meat, unsalted nuts (except peanuts – a legume), fresh squeezed lemon or lime juice (as dressing), flaxseed or rapeseed oil (as dressing), coffee and tea (w/o sugar, milk, honey, or cream), all salt-free spices.
  • Allowed but with major restrictions: dried fruit, salted seafood, fat meat, potatoes (two medium-sized per day), honey, cured meats
  • Prohibited: all milk and dairy products, all grain products (including corn and rice), all legumes, canned food except tomatoes, candy, ice cream, soft drinks, juices, syrups, alcohol, sugar, and salt

What Did They Find After Three Weeks?

  • Average weight dropped from 65.2 kg (144 lb) to 62.9 (139 lb)
  • Average body mass index fell from 22.2 to 21.4
  • Average waist circumference decreased from 74.3 cm (29.25″) to 72.6 cm (28.58″)
  • Average systolic blood pressure fell from 110 to 104 mmHg
  • plasminogen activator inhibitor-1 decreased from 5.0 kIE/l to 2.8 kIE/l
  • All of these changes were statistically significant

The researchers looked at a number of other blood tests and didn’t find any significant differences.

Five men and three women completed the study. Of the 20 who originally signed up, one could not fulfill the diet, three became ill (no details), two failed to show up.

So What?

That’s a remarkable weight loss over just three weeks for slender people eating ad lib.

The study authors concluded that these paleo diet-induced changes could reduce risk for cardiovascular disease. They called for a larger study with a control group. (If it’s been done, I haven’t found it yet.)

Sounds reasonable.

It’s too soon to say whether the paleo diet is just a fad.  It will depend somewhat on short- and long-term health effects of paleo-style eating, which may take years to clarify.  On the other hand, it’s hard to imagine large swaths of the population giving up grains, legumes, and dairy products, even if it’s a healthier way of eating.

Steve Parker, M.D.

PS: You’d think they would have said more about the three participants who got sick, rather than leave us wondering if the diet made them ill.

PPS:  I’m considering whether the paleo diet is healthy for people with diabetes.  Follow my progress at PaleoDiabetic.com.

Reference: Österdahl, M; Kocturk, T; Koochek, A; Wändell, PE. Effects of a short-term intervention with a paleolithic diet in healthy volunteers. European Journal of Clinical Nutrition, 62 (2008): 682-685.