Tag Archives: osteoporosis

Reinagel Ponders Whether Calcium Supplements Are Safe

 

Death in a bottle?

Death in a bottle?

Monica Reinagel is a smart and media-savvy nutritionist who brought me on board as a blogger at NutritionData many years ago. Click the link below for her surprising conclusion on calcium supplementation.

Monica writes:

“The National Osteoporosis Foundation published a new report this week, insisting that calcium supplements are safe for your heart. Two weeks ago, Johns Hopkins cardiologist Erin Michos published a paper saying the opposite.

She claims that the NOF review (which was funded by a pharmaceutical company that makes calcium supplements) omitted certain studies (such as the ones she included in her own review) that might have changed the conclusion.

These are just the latest two volleys in a five-year-long tennis match between experts on whether you should or shouldn’t take calcium supplements.  And you thought politics was divisive.”

Source: Calcium Supplements: Safe or Not?

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Filed under Heart Disease

Elders on a Weight-Loss Diet Preserve Bone Mineral Density With Resistance Training, Not Aerobic Exercise

according to an article at MedPageToday.

"One more rep then I'm outa here!"

“One more rep then I’m outa here!”

In the study at hand, the two experimental groups had about 60 participants each, so it was a relatively small study. (In general, the larger the study, the more reliable the findings.) Most participants were white women; mean age was 69. The experimental intervention ran for five months. An excerpt:

In one trial, the participants were randomized to a structured resistance training program in which three sets of 10 repetitions of eight upper and lower body exercises were done 3 days each week at 70% of one repetition maximum for 5 weeks, with or without calorie restriction of 600 calories per day.
In the second study, participants were randomized to an aerobic program which was conducted for 30 minutes at 65% to 70% heart rate reserve 4 days per week, with or without calorie restriction of 600 calories per day.

The beneficial bone effect was seen at the hip but not the lumbar spine. (I’ve treated lots of hip and lumbar spine fractures. If I’m going to break one of those bones, I’d rather it be the spine.)

Thin old bones—i.e., osteoporotic ones—are prone to fractures. Maintaining or improving bone mineral density probably prevents age-related fractures. In a five-month small study like this, I wouldn’t expect the researchers to find any fracture rate reduction; that takes years.

Most mainstream articles on prevention and treatment of osteoporosis mention “weight-bearing” exercises as what you should do, like walking, jogging, tai chi, and volleyball. The current study adds resistance training to our therapeutic armamentarium. Resistance training is also called weight training or strength training.  

Most elders starting a weight-training program should work with a personal trainer.

Steve Parker, M.D.

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Filed under Exercise

Do Calcium Supplements Cause Heart Attacks?

A new European study suggests that calcium supplements almost double the risk of having a heart attack, at least in Germans.  You can read the full report in the current issue of Heart.

The medical literature on this issue is a confusing mess.  In other words, lots of conflicting results.

Huge numbers of women in the U.S. are taking calcium supplements either to treat or prevent osteoporosis and the associated broken bones (e.g., hips, wrists, spine).

What I’d like to know, and what nobody knows, is what is the effect of calcium supplementation on average longevity and quality of life.  Maybe I’d accept a higher risk of heart attack if calcium supplementation prolonged lifespan by two years.

In the interest of brevity, I’ll just say that the best way to get your calcium is probably through food rather than supplements.

Shereen Jegtvig has an article at About.com listing foods rich in calcium.

Exercise can also help keep your bones strong and break-resistant.

Steve Parker, M.D.

PS: If your doctor has you on a calcium supplement, you’d best get his blessing before you stop it.

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Filed under Heart Disease, Supplements

Low-Fat and Low-Carb Diets End Battle in Tie After Two Years, But…

Dieters on low-fat and low-carb diets both lost the same amount of weight after two years, according to a just-published article in Annals of Internal Medicine.  Both groups received intensive behavioral treatment, which may be the key to success for many.  Low-carb eating was clearly superior in terms of increased HDL cholesterol, which may help prevent heart disease and stroke.

The study was funded by the National Institutes of Health and was carried out in Denver, St. Louis, and Philadelphia.

How Was It Done?

Healthy adults aged 18-65 were randomly assigned to either a low-fat or low-carbohydrate diet.  Average age was 45.  Average body mass index was 36 (over 25 is overweight; over 30 is obese).  Of the 307 participants, two thirds were women.  People over 136 kg (299 lb) were excluded from the study—I guess because weight-loss through dieting is rarely successful at higher weights.  Diabetics were excluded. 

The low-carb diet:  Essentially the Atkins diet with a prolonged induction phase (12 weeks instead of two).  Started with maximum of 20 g carbs daily, as low-carb vegetables.  Increase carbs by 5 g per week thereafter as long as weight loss progressed as planned.  Fat and protein consumption were unlimited.  The primary behavioral goal was to limit carb consumption.

The low-fat diet:  Calories were limited to 1200-1500 /day (women) or 1500-1800 (men).  [Those levels in general are too low, in my opinion.]  Diet was to consist of about 55% of calories from carbs, 30% from fat, 15% from protein.  The primary behavioral goal was to limit overall energy (calorie) intake. 

Both groups received frequent, intensive in-person group therapy—lead by dietitians and psychologists—periodically over two years, covering such topics as self-monitoring, weight-loss tips, management of weight regain and noncompliance with assigned diet.  Regular walking was recommended.

Body composition was measured periodically with dual X-ray absorptiometry.

What Did They Find?

Both groups lost about 11% of initial body weight, but tended to regain so that after two years, both groups average losses were only 7% of initial weight.  Weight loss looked a little better at three months in the low-carb group, but it wasn’t statistically significant. 

The groups had no differences in bone density or body composition.

No serious cardiovascular illnesses were reported by participants.  During the first six months, the low-carb group reported more bad breath, hair loss, dry mouth, and constipation.  After six months, constipation in the low-carb group was the only symptom difference between the groups.

During the first six months, the low-fat group had greater decreases in LDL cholesterol (with potentially less risk of heart disease), but the difference did not persist for one or two years.

Increases in HDL cholesterol (potentially heart-healthy) persisted throughout the study for the low-carb group.  The increase was 20% above baseline.

About a third of participants in both groups dropped out of the study before the two years were up.  [Not unusual.]

My Comments

Contrary to several previous studies that suggested low-carb diets are more successful than low-fat, the study at hand indicates they are equivalent as long as dieters get intensive long-term group behavioral intervention. 

Low-carb critics warn that the diet will cause osteoporosis, a dangerous thinning of the bones that predisposes to fractures.  This study disproves that.

Contrary to widespread criticism that low-carb eating—with lots of fat and cholestrol— is bad for your heart, this study notes a sustained elevation in HDL cholesterol (“good cholesterol”) on the low-carb diet over two years.  This also suggests the low-carbers  followed the diet fairly well.  The investigators also note that low-carb eating tends to produce light, fluffy LDL cholesterol, which is felt to be less injurious to arteries compared to small, dense LDL cholesterol.

A major strength of the study is that it lasted two years, which is rare for weight-loss diet research.

A major weakness is that the investigators apparently didn’t do anything to document the participants’ degree of compliance with the assigned diet.  It’s well known that many people in this setting can follow a diet pretty well for two to four months.  After that, adherence typically drops off as people go back to their old habits.  The group therapy sessions probably improved compliance, but we don’t know since it wasn’t documented. 

How often do we hear “Diets don’t work.”  Well, that’s just wrong.

Overall, it’s an impressive study, and done well. 

Individuals wishing to lose weight on their own can’t replicate these study conditions because of the in-person behavioral intervention component.  There are lots of self-help calorie-restricted balanced diets (e.g., Sonoma Diet, The Zone,  Advanced Mediterranean Diet) and low-carb diets (e.g., Atkins Diet, Banting’s Letter on Corpulence, Low-Carb Mediterranean or Ketogenic Mediterranean Diets).  On-line support groups—e.g. Low Carb Friends and SparkPeople and 3 Fat Chicks on a Diet—could supply some necessary behavioral intervention strategies and support.  

Choosing a weight-loss program is not as easy as many think.  [Well, I’ll admit that choosing the wrong one is easy.]  I review the pertinent issues in my “Prepare for Weight Loss” page.

Steve Parker, M.D.

Reference: Foster, Gary, et al.  Weight and metabolic outcomes after 2 years on a low-carbohydrate versus low-fat diet: a randomized trial. Annals of Internal Medicine, 153 (2010): 147-157   PMID: 20679559

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Filed under Carbohydrate, Fat in Diet, ketogenic diet, Overweight and Obesity, Weight Loss

My Ketogenic Mediterranean Diet: Day 54 + Potassium Deficiency

The Monument Valley Navajo Tribal ParkWeight: 154 lb

Transgressions: TNTC (too numerous to count)

Exercise: none

Comments

The Potassium Problem

My current food intake on the Ketogenic Mediterranean Diet appears to be low in potassium, which might have long-term health consequences if followed for many months or years.  According to the Linus Pauling Institute’s Micronutrient Information Center, adequate potassium intake apparently decreases blood pressure, reduces salt sensitivity, decreases risk of kidney stones, and protects against osteoporosis and stroke. 

These associations between higher potassium intake and lower condition rates are based mostly on observational studies of populations in which some people eat little potassium and others eat a lot.  It’s assumed that people with higher potassium intake are eating more fruits and vegetables, not taking supplements. 

The Linus Pauling Institute agrees with the U.S. Institute of Medicine’s  “Adequate Intake” value for potassium of 4,700 mg daily for average adults.  The current U.S. Food and Drug Administration Daily Value is about 3,500 mg.  I’m only getting 2,000 mg/day now. 

Multivitamin/multimineral supplements in the U.S. provide a maximum of 99 mg potassium (by law?).  I bought a potassium gluconate supplement at CVS Pharmacy last night: 90 mg potassium, a drop in the bucket.  I dropped into a Hi Health vitamin store (health food store?) today and would swear I saw a combined magnesium and potassium supplement that contained 150 mg potassium. 

Excess potassium intake can be life-threatening in certain situations such as kidney impairment and use of medications like potassium-sparing diuretics and ACE inhibitors. 

Relatively high meat intake tends to create an acidic environment in the body, which our bones help to buffer or counteract.  In the process, calcium in our bones is mobilized and can be lost through urine.  The end result after many years is osteoporosis: thin brittle bones easily broken.  And perhaps calcium-containing kidney stones.  These are traditional concerns about high-protein diets. 

Many fruits and vegetables are considered naturally alkaline, tending to counteract the acid production of other foods. 

I see sporadic reports about potassium bicarbonate supplementation acting as an acid buffer and reducing urinary calcium loss.  Potassium citrate may do the same.  Even potassium chloride may reduce urinary calcium loss separate from any acid buffering capacity (which it shouldn’t have, anyway).  Are those supplements available without a physician’s prescription?  Health food store perhaps?  [Not in Hi Health.]  Would a salt substitute containing potassium chloride be a reasonable source of potassium? 

How about reducing fruit and vegetable consumption, replacing them with a potassium bicarbonate supplement?  Probably not a fair trade.  The food has myriad other nutrients that probably promote health and longevity. 

These potassium-related health concerns are much less bothersome, perhaps nonexistent, when I admit that very few people will follow a very low-carb ketogenic diet for longer than several months.  But it’s an issue.

On the other hand, maybe I worry too much.  Remember, the foods I choose are giving me 2,000 mg potassium daily.  The total potassium could be lower or higher depending on one’s choice of food items.  I have the 1993 edition of Understanding Nutrition, a popular college textbook in basic nutrition.  The table of Recommended Dietary Allowances doesn’t even list potassium.  The text mentions an estimated minimum requirement for potassium of 2,000 mg/day.  The Canadian minimum requirement was 1,170 mg/day. 

About My Diet Transgressions

After 53 days of very low-carb eating, I decided to take a break, a cheat day.  The family was celebrating a milestone.  We drove 2 hours and 20 minutes, one way, to eat at Eat At Joe’s Barbecue in Wikiup, Arizona.  Best Texas-style barbecue outside of Texas.  I had brisket, baked beans, half a roll, cole slaw, stuffed jalapenos, Shiner Bock beer, and cherry pie.  Probably ate 3,500 calories today instead of my usual 1,850.  Expect my weight will be up 2–3 lb tomorrow.  We’ll see how far and how long this transgression sets me back.  All in the name of Science, of course.

Steve

Update October 25, 2009

At the supermarket today I found an over-the-counter potassium supplement for anyone wanting more non-food potassium in their diet:  Morton Salt Substitute.  A quarter teaspoon has 610 mg potassium.  It contains potassium chloride, fumaric acid, tricalcium phosphate, and monocalcium phosphate.  The container carries a warning: “Consult a physician before using any salt substitute.”  I found it on the shelf near the regular salt.  I also saw a product that was half salt (NaCl) and half potassium chloride (KCl).  I haven’t tried Morton Salt Substitute yet.  It’s a cheaper source of potassium than a potassium gluconate supplement.   

-Steve

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Filed under My KMD Experience

What’s the Best Diet to Prevent Osteoporosis?

MedicalHappy Healthy Long Life, a blog by an anonymous “medical librarian,” has a thought-provoking article on the best diet to prevent osteoporosis: high in fruits and vegetables, low in animal proteins.

Osteoporosis is a common disease of the elderly, affecting women much more than men.  It causes thin, brittle bones that break easily.  You know all those little old ladies with broken hips?  Nearly all have osteoporosis. 

The standard prescription for prevention is weight-bearing exercise on a regular basis, and adequate intake of calcium and vitamin D.  The aforementioned blog post rejects the calcium recommendation, at least.

I haven’t reviewed this issue for many years and I just discovered Happy Healthy Long Life, so I have no opinion on validity of the post.

Steve Parker, M.D.

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Are High-Protein Weight-Loss Diets Safe and Effective?

Animal protein

Animal protein

According to researchers at Tufts University, high-protein weight-loss diets may be effective and safe except for people prone to kidney stones, chronic kidney disease, and people with diabetes.  Long-term effects on bone health – osteoporosis, specifically – might be a problem.

High-protein weight-loss diets have been popular for a while.  “Protein Power” by Drs. Michael and Mary Eades is an example.  The Atkins diet may be, too.  If you increase the protein in your diet, you generally are decreasing carbohydrates or fat, or both, at the same time.   

I found a scientific review article from way back in 2002 and thought I’d share some of the highlights.  The authors seem very thorough; the article has 150 citations of other research articles. 

Note that the RDA – recommended dietary allowance – for protein is 0.8 gm/kg.  The typical U.S. resident eats about 1.2 gm/kg of protein daily, which is about 15% of total energy (calorie) intake.   Public health agencies recommend that we get 15% of our energy from protein, 30% from fat, and 55% from carbohydrate.  The authors of the study at hand propose that a high-protein diet be defined as:

  • protein intake of at least 25% of energy in weight-stable individuals, or
  • at least 1.6 gm/kg (of ideal body weight)  in people actively losing weight

Here are some of the authors’ points I found interesting:

  1. Higher-protein meals do seem to suppress hunger and enhance satiety, so high-protein dieters probably eat less (average 9% less calories).  It’s unknown if the effect lasts longer than six months.  Most of the evidences is much shorter-term.
  2. High-protein intake increases the thermic effect of feeding, meaning energy expenditure increases simply as a result of eating protein.  In other words, it takes energy to process the food we eat.  Compared with fats and carbohydrates, protein contributes twice as much to the thermic effect of feeding.  Most of the thermic effect of protein results from protein synthesis, i.e., the production of new proteins, which requires energy.  This has a minimal influence on body weight. 
  3. The authors write that “these studies do not support a role for high dietary protein in preventing loss of lean tissue during negative energy balance [actively cutting calories to lose weight], provided that dietary protein intake at least meets the RDA.”   
  4. They found only one study comparing a high-protein diet (25% of calories) with a low-fat, high-carbohydrate diet (12% protein).  Both diets were 30% fat.  Both groups could eat all they wanted.  Weight and fat loss were greater in the high-protein group, about twice as much. 
  5. High-protein diets over the long run may cause low-grade metabolic acidosis, leading to net loss of body calcium through the urine, with associated weak bones and kidney stones.   Animal proteins in particular do this.  Bone loss may be alleviated by calcium supplementation.  Fruits and vegetables may counteract the acidosis effect.  Nearly all of these statements are based on short-term studies.
  6. People with chronic kidney disease (ask your doctor) have slower disease progression and live longer if they limit protein to the RDA level. 
  7. Animal protein intake is directly related to risk of symptomatic kidney stones.
  8. Protein produces a blood glucose response, although not as much as with carbohydrate.  Insulin response is also seen.  In type 2 diabetics, the insulin response to 50 grams of animal protein was the same as to 50 grams of glucose.  A few studies suggest that in type 2 diabetics a high-protein diet may be detrimental to glucose control and/or insulin sensitivity.  Also note that people with diabetes are prone to chronic kidney disease, which could be worsened with a high-protein diet.  

Take-Home Points

See first paragraph.  The article authors may have different opinions now, based research published over the last seven years. 

Steve Parker, M.D.

Reference:  Eisenstein, Julie, et al.  High-protein weight-loss diets:  Are they safe and do they work?  A revew of the experimental and epidemiologic data.  Nutrition Reviews, 60 (2002): 189-200.

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Filed under Diabetes Complications, Protein, Weight Loss