Tag Archives: death

Supplemental Omega-3 Fats’ Effect on Heart Disease, Stroke, Cancer, and Death: No Relationship In a General Population

Salmon is one the the cold-water fatty fish loaded with omega-3 fatty acids

Salmon is one the the cold-water fatty fish loaded with omega-3 fatty acids

I’ve been sitting on this research report a few years, waiting until I had time to dig into it. That time never came. The full report is free online (thanks, British Medical Journal!). I scanned the full paper to learn that nearly all the studies in this meta-analysis used fish oil supplements, not the cold-water fatty fish the I recommend my patients eat twice a week.

Here’s the abstract:

Objective: To review systematically the evidence for an effect of long chain and shorter chain omega 3 fatty acids on total mortality, cardiovascular events, and cancer.

Data sources: Electronic databases searched to February 2002; authors contacted and bibliographies of randomised controlled trials (RCTs) checked to locate studies.

Review methods Review of RCTs of omega 3 intake for 3 6 months in adults (with or without risk factors for cardiovascular disease) with data on a relevant outcome. Cohort studies that estimated omega 3 intake and related this to clinical outcome during at least 6 months were also included. Application of inclusion criteria, data extraction, and quality assessments were performed independently in duplicate.

Results: Of 15 159 titles and abstracts assessed, 48 RCTs (36 913 participants) and 41 cohort studies were analysed. The trial results were inconsistent. The pooled estimate showed no strong evidence of reduced risk of total mortality (relative risk 0.87, 95% confidence interval 0.73 to 1.03) or combined cardiovascular events (0.95, 0.82 to 1.12) in participants taking additional omega 3 fats. The few studies at low risk of bias were more consistent, but they showed no effect of omega 3 on total mortality (0.98, 0.70 to 1.36) or cardiovascular events (1.09, 0.87 to 1.37). When data from the subgroup of studies of long chain omega 3 fats were analysed separately, total mortality (0.86, 0.70 to 1.04; 138 events) and cardiovascular events (0.93, 0.79 to 1.11) were not clearly reduced. Neither RCTs nor cohort studies suggested increased risk of cancer with a higher intake of omega 3 (trials: 1.07, 0.88 to 1.30; cohort studies: 1.02, 0.87 to 1.19), but clinically important harm could not be excluded.

Conclusion: Long chain and shorter chain omega 3 fats do not have a clear effect on total mortality, combined cardiovascular events, or cancer.

Reference: Hooper, Lee et al. Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review. BMJ  2006;332:752-760 (1 April), doi:10.1136/bmj.38755.366331.2F (published 24 March 2006).

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Filed under coronary heart disease, Diabetes Complications, Fat in Diet, Fish, Heart Disease, Longevity, Stroke

Alcohol Consumption Linked to Lower Risk of Death and Kidney Disease in Type 2 Diabetics

…according to an article at MedPageToday. Over 6,000 T2 diabetics were followed for over five years.

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Lower Risk of Death and Heart Disease With Olive Oil

 

Olive oil and vinegar

Olive oil consumption is linked to lower risk of death and heart disease in a Spanish population, according to the American Journal of Clinical Nutrition.

Olive oil figures prominently in my Ketogenic Mediterranean Diet and Low-Carb Mediterranean Diet.

-Steve

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Filed under Fat in Diet, Heart Disease, Longevity, olive oil

Meat and Mortality

Red meat and processed meat consumption are associated with “modest” increases in overall mortality and deaths from cancer and cardiovascular disease, according to National Institutes of Health researchers.  This goes for both sexes.

Data are from the huge NIH-AARP Diet and Heart Study, a prospective cohort trial involving  over 550,000 U.S. men and women aged 50-71 at the time of enrollment.  Food consumption was determined by questionnaire.  Over the course of 10 years’ follow-up, over 65,000 people died.  Investigators looked to see if causes of death were related to meat consumption.

What do they mean by red meat, processed meat, and white meat?

Red meat:  all types of beef and pork (wasn’t there a U.S. ad campaign calling pork “the other white meat”?}

White meat:  chicken, turkey, fish

Processed meat:  bacon, red meat sausage, poultry sausage, luncheon meats (red and white), cold cuts (red and white), ham, regular hotdogs, low-fat poultry hotdogs, etc.

What did they find?

See the first paragraph above.

Studies like this typically look at the folks who ate the very most of a given type of food, those who ate the very least, then compare differences in deaths between the two groups.  That’s what they did here, too.  For instance, the people who ate the very most red meat ate 63 grams per 1000 caories of food daily.  Those who ate the least ate 10 grams per 1000 cal of food daily.  That’s about a six-fold difference.  Many folks eat 2000 calories a day.  The high red meat eaters on 2000 cals a day would eat 123 grams, or 4.4 ounces of red meat.  The low red meat eaters on 2000 cals/day ate 20 grams, or 0.7 ounces.

The heavy consumers of processed meats ate 23 grams per 1000 cal of food daily.  The lowest consumers ate 1.6 grams per 1000 cal.

Comparing these two quintiles of high and low consumption of red and processed meats, overall mortality was 31-36% higher for the heavy red meat eaters, and 16-25% higher for the heavy processed meat eaters.  (The higher numbers in the ranges are for women.)  Similar numbers were found when looking at cancer deaths and cardiovascular deaths (heart attacks, strokes, ruptured aneurysms, etc).

It’s not proof that heavy consumption of red and processed meats is detrimental to longevity, but it’s suggestive.  The “Discussion” section of the article reviews potential physiological mechanisms for premature death.

The researchers called these differences “modest.”  I guess they use “modest” since most people eat somewhere between these extreme quintiles.  The numbers incline me  to stay out of that “highest red and processed meat consumer” category, and lean more towards white meat and fish.

The study at hand is from 2009.  Another research report in Archives of Internal Medicine this month supported similar conclusions. (Click for Zoë Harcombe’s critique of the study.)

The traditional Mediterranean diet and Advanced Mediterranean Diet are naturally low in red and processed meats, but not designed specifically for folks with diabetes.

Steve Parker, M.D. 

Reference:  Sinha, Rashmi, et al.  Meat intake and mortality: a prospective study of over half a million peopleArchives of Internal Medicine, 169 (2009): 562-571.

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Filed under cancer, coronary heart disease, Stroke

Greater Risk of Death in Diabetics with Lower Salt Intake

Have you noticed the national push for lower salt consumption? It’s driven by the idea that lower consumption will reduce the risk of heart attacks, strokes, and death, supposedly mediated through lower blood pressure.

The latest issue of Diabetes Care has a research report showing a greater risk of death in type 2 diabetics with lower salt consumption over the course of 10 years. Yes, you read that right: greater risk of death with lower salt consumption.

Keep your eyes and ears open on this issue.

Steve Parker, M.D.

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Exercise, Part 1: Exercise Postpones Death

Earlier this month, many folks made New Years’ resolutions to start exercising in conjunction with their other resolution to lose excess weight. I’ve got bad news for them.

Exercise is overrated as a pathway to major weight loss.

Sure, a physically inactive young man with only five or 10 pounds (2 to 4 kg) to lose might be able to do it simply by starting an exercise program. That doesn’t work nearly as well for women. The problem is that exercise stimulates appetite, so any calories burned by exercise tend to be counteracted by increased food consumption.

"Should I go with aerobic or strength training....?"

On the other hand, exercise is particularly important for diabetics and prediabetics in two respects: 1) it helps in avoidance of overweight, especially after weight loss, and 2) it helps control blood sugar levels by improving insulin resistance, perhaps even bypassing it.

Even if it doesn’t help much with weight loss, regular physical activity has myriad general health benefits. First, let’s look at its effect on death rates.   

EXERCISE PREVENTS DEATH

As many as 250,000 deaths per year in the United States (approximately 12% of the total) are attributable to a lack of regular physical activity. We know now that regular physical activity can prevent a significant number of these deaths.

Exercise induces metabolic changes that lessen the impact of, or prevent altogether, several major illnesses, such as high blood pressure, coronary artery disease, diabetes, and obesity. There are also psychological benefits. Even if you’re just interested in looking better, awareness of exercise’s other advantages can be motivational.

Exercise is defined as planned, structured, and repetitive bodily movement done to improve or maintain physical fitness.

Physical fitness is a set of attributes that relate to your ability to perform physical activity. These attributes include resting heart rate, blood pressure at rest and during exercise, lung capacity, body composition (weight in relation to height, percentage of body fat and muscle, bone structure), and aerobic power.

Aerobic power takes some explanation. Muscles perform their work by contracting, which shortens the muscles, pulling on attached tendons or bones. The resultant movement is physical activity. Muscle contraction requires energy, which is obtained from chemical reactions that use oxygen. Oxygen from the air we breathe is delivered to muscle tissue by the lungs, heart, and blood vessels. The ability of the cardiopulmonary system to transport oxygen from the atmosphere to the working muscles is called maximal oxygen uptake, or aerobic power. It’s the primary factor limiting performance of muscular activity.

Aerobic power is commonly measured by having a person perform progressively more difficult exercise on a treadmill or bicycle to the point of exhaustion. The treadmill test starts at a walking pace and gets faster and steeper every few minutes. The longer the subject can last on the treadmill, the greater his aerobic power. A large aerobic power is one of the most reliable indicators of good physical fitness. It’s cultivated through consistent, repetitive physical activity.

Physical Fitness Effect on Death Rates

Regular physical activity postpones death.

Higher levels of physical fitness are linked to lower rates of death primarily from cancer and cardiovascular disease (e.g., heart attacks and stroke). What’s more, moving from a lower to a higher level of fitness also prolongs life, even for people over 60.

Part 2 of this series will cover all the other health benefits of exercise. Part 3 will outline specific exercise recommendations, such as the type and duration of activity.

Steve Parker, M.D.

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Low-Carb Diets Killing People?

Animal-based low-carb diets are linked to higher death rates, according to a recent study in the Annals of Internal Medicine.  On the other hand, a vegetable-based low-carb diet was associated with a lower mortality rate, especially from cardiovascular disease.

As always, “association is not causation.”

It’s just a matter of time before someone asks me, “Haven’t you heard that low-carb diets cause premature death?”  So I figured I’d better take a close look at the new research by Fung and associates.

It’s pretty weak and unconvincing.  I have little to add to the cautious editorial by William Yancy, Matthew Maciejewski, and Kevin Schulman published in the same issue of Annals.

The study at hand was observational over many years, using data from the massive Nurses’ Health Study and Health Professionals’ Follow-up Study.  To find the putative differences in mortality, the researchers had to compare the participants eating the most extreme diets.  The 80% of study participants eating in between the extremes  were neutral in terms of death rates.

They report that “…the overall low-carbohydrate diet score was only weakly associated with all-cause mortality.”  Furthermore,

These results suggest that the health effects of a low-carbohydrate diet may depend on the type of protein and fat, and a diet that includes mostly vegetable sources of protein and fat is preferable to a diet with mostly animal sources of protein and fat.

In case you’re wondering, all these low-carb diets derived between 35 and 42% of energy (total calories) from carbohydrate, with an average of 37%.  Anecdotally, many committed low-carbers chronically derive 20% of calories form carbohydrate (100 g of carb out of 2,000 calories/day).  The average American eats 250 g of carb daily, 50-60% of total calories.

Yancy et al point out that “Fung and coworkers did not show a clear dose-response relationship in that there was not a clear progression of risk moving up or down the diet deciles.”  If animal proteins and fats are lethal, you’d expect to see some dose-response relationship, with more deaths as animal consumption gradually increases over the deciles.

ResearchBlogging.orgThe Fung study is suggestive but certainly not definitive.  Anyone predisposed to dietarycaution who wants to eat lower-carb might benefit from eating fewer animal sources of protein and fat, and more vegetable sources.  Fung leaves it entirely up to you to figure out how to do that. Compared to an animal-based low-carb diet, the healthier low-carb diet must subsitute more low-carb vegetables and higher-fat plants like nuts, seeds, seed oils and olive oil, and avocadoes, for example.  What are higher-protein plants?  Legumes?

You can see how much protein and fat are in your favorite vegetables at the USDA Nutrient Database.

The gist of Fung’s study dovetails with the health benefits linked to low-meat diets such as traditional Mediterranean and DASH.  On the other hand, if an animal-based low-carb diet helps keep a bad excess weight problem under control, it too may by healthier than the standard American diet.

See the Yancy editorial for a much more detailed and cogent analysis.  As is so often the case, “additional studies are needed.”

Steve Parker, M.D.

Reference: Fung TT, van Dam RM, Hankinson SE, Stampfer M, Willett WC, & Hu FB (2010). Low-carbohydrate diets and all-cause and cause-specific mortality: two cohort studies. Annals of internal medicine, 153 (5), 289-98 PMID: 20820038

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Filed under Carbohydrate, coronary heart disease, Vegetables