July 7, 2015 · 6:48 AM
MRI scan of brain
The NYT’s Well blog has the details. The brain’s hippocampus is a critical center for memory. Alzheimers disease is associated with a gene called apo-E4. Carriers of that gene who exercise regularly have less shrinkage of the hippocampus than non-exercisers.
To PROVE that regular exercise prevents dementia-related shrinkage of the hippocampus, you’d have to force some folks to exercise and stop others who wanted to exercise. A couple years later, scan their brains and compare the two groups. That study may never be done.
The Mediterranean diet also seems to prevent or forestall dementia.
Steve Parker, M.D.
July 30, 2014 · 8:30 PM
Nobody knows. A recent report out of Germany suggests that pioglitazone does prevent dementia, but it’s not a very strong linkage. If it works, I wonder if it’s simply related to better control of blood sugar, which could be accomplished with a variety of means. Pioglitazone (aka Actos) is a type 2 diabetes drug in the TZD class. You could call it an “insulin sensitizer.”
The best popular press report I’ve seen is at Bloomberg.
German researchers went fishing for associations in a huge database of patients and drug usage. Their formal report hasn’t even been published yet. A five-year study was recently initiated to further investigate the possibility that piogoitazone prevents dementia. I doubt this will pan out.
Steve Parker, M.D.
May 15, 2014 · 8:36 AM
Well, maybe that’s a bit of an overstatement. Preserved brain function and the Mediterranean diet were positively associated in a study involving Americans in Utah. This fits with prior observations that the Mediterranean diet prevents dementia.
In the study at hand, the DASH diet (Dietary Approaches to Stop Hypertension) also protected the brain:
Higher levels of compliance with both the DASH and Mediterranean dietary patterns were associated with consistently higher levels of cognitive function in elderly men and women over an 11-y period. Whole grains and nuts and legumes were positively associated with higher cognitive functions and may be core neuroprotective foods common to various healthy plant-centered diets around the globe.
See the American Journal of Clinical Nutrition for details.
December 19, 2013 · 4:32 PM
“Let’s work on getting those blood sugars down, honey.”
On the heels of a report finding no association between Alzheimer’s disease and abnormal blood sugar metabolism, MedPageToday features an new study linking high blood sugars to future development of dementia. And diabetics with sugar levels higher than other diabetics were more prone to develop dementia.
Some of you have already noted that not all cases of dementia are Alzheimer’s dementia. But Alzheimer’s accounts for a solid majority of dementia cases, about eight in 10 cases.
Some quotes from MedPageToday:
During a median follow-up of 6.8 years, 524 participants [of the 2,000 total] developed dementia, consisting of 74 with diabetes and 450 without. Patients without diabetes and who developed dementia had significantly higher average glucose levels in the 5 years before diagnosis of dementia (P=0.01). The difference translated into a hazard ratio of 1.18 (95% CI 1.04-1.33).
Among the patients with diabetes, glucose levels averaged 190 mg/dL in those who developed dementia versus 160 mg/dL in those who did not. The difference represented a 40% increase in the hazard for dementia (HR 1.40, 95% CI 1.12-1.76).
—Steve Parker, M.D.
Reference: Crane PK et al. “Glucose Levels and Risk of Dementia” N Engl J Med 2013; 369: 540-548.
Reminder: Conquer Diabetes and Prediabetes is now available on Kindle.
September 30, 2013 · 4:56 AM
- I like fish, but raw whole dead fish leave me cold
Supplementation with omega-3 fatty acids does not help prevent age-related cognitive decline and dementia, according to an article at MedPage Today.
The respected Cochrane organization did a meta-analysis of three pertinent studies done in several countries (Holland, UK, and ?).
The investigators leave open the possibility that longer-term studies—over three years—may show some benefit.
I leave you with a quote from the MedPage Today article:
And while cognitive benefits were not demonstrated in this review, Sydenham and colleagues emphasized that consumption of two servings of fish each week, with one being an oily fish such as salmon or sardines, is widely recommended for overall health benefits.
Steve Parker, M.D.
Sydenham E, et al “Omega 3 fatty acid for the prevention of cognitive decline and dementia” Cochrane Database of Systematic Reviews 2012; DOI: 10.1002/14651858.CD005379.pub3.
August 14, 2013 · 4:13 AM
Compared with non-diabetics in the study, T2s had brain atrophy (shrinkage on MRI scans) and cognitive deficits reminiscent of pre-clinical Alzheimer’s disease.
Click for details at Diabetes Care.
August 12, 2013 · 8:17 AM
Don’t wait to take action until it’s too late
Insulin resistance and high blood insulin levels promote age-related degeneration of the brain, leading to memory loss and dementia according to Robert Krikorian, Ph.D. He’s a professor in the Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati Academic Health Center. He has an article in a recent issue of Current Psychiatry – Online.
Proper insulin signaling in the brain is important for healthy functioning of our brains’ memory centers. This signaling breaks down in the setting of insulin resistance and the associated high insulin levels. Dr. K makes much of the fact that high insulin levels and insulin resistance are closely tied to obesity. He writes that:
“Waist circumference of ≥100 cm (39 inches) is a sensitive, specific, and independent predictor of hyperinsulinemia for men and women and a stronger predictor than body mass index, waist-to-hip ratio, and other measures of body fat.”
Dr. Krikorian thinks that dietary approaches to the prevention of dementia are effective yet underutilized. He mentions reduction of insulin levels by restricting calories or a ketogenic diet: they’ve been linked with improved memory in middle-aged and older adults.
Dr. Krikorian suggests the following measures to prevent dementia and memory loss:
- eliminate high-glycemic foods like processed carbohydrates and sweets
- replace high-glycemic foods with fruits and vegetables (the higher polyphenol intake may help by itself)
- certain polyphenols, such as those found in berries, may be particularly helpful in improving brain metabolic function
- keep your waist size under 39 inches, or aim for that if you’re overweight
I must mention that many, perhaps most, dementia experts are not as confident as Dr. Krikorian that these dietary changes are effective. I think they probably are, to a degree.
The Mediterranean diet is high in fruits and vegetables and relatively low-glycemic. It’s usually mentioned by experts as the diet that may prevent dementia and slow its progression.
Read the full article.
I’ve written before about how blood sugars in the upper normal range are linked to brain degeneration. Dr. Krikorian’s recommendations would tend to keep blood sugar levels in the lower end of the normal range.
Steve Parker, M.D.
PS: Speaking of dementia and ketogenic, have you ever heard of the Ketogenic Mediterranean Diet? (Free condensed version here.)
April 6, 2013 · 2:00 AM
Potential answers are in the American Journal of Clinical Nutrition (2012). I quote:
For hypertension, coronary heart disease, and stroke, there is convincing evidence that increasing the consumption of vegetables and fruit reduces the risk of disease. There is probable evidence that the risk of cancer in general is inversely associated with the consumption of vegetables and fruit. In addition, there is possible evidence that an increased consumption of vegetables and fruit may prevent body weight gain. As overweight is the most important risk factor for type 2 diabetes mellitus, an increased consumption of vegetables and fruit therefore might indirectly reduces the incidence of type 2 diabetes mellitus. Independent of overweight, there is probable evidence that there is no influence of increased consumption on the risk of type 2 diabetes mellitus. There is possible evidence that increasing the consumption of vegetables and fruit lowers the risk of certain eye diseases, dementia and the risk of osteoporosis. Likewise, current data on asthma, chronic obstructive pulmonary disease, and rheumatoid arthritis indicate that an increase in vegetable and fruit consumption may contribute to the prevention of these diseases. For inflammatory bowel disease, glaucoma, and diabetic retinopathy, there was insufficient evidence regarding an association with the consumption of vegetables and fruit.
It bothers me that vegetables and fruits are lumped together: they’re not the same.
All of my diets—Advanced Mediterranean, Low-Carb Mediterranean, and Ketogenic Mediterranean—provide plenty of fruits and vegetables.
Filed under cancer, Dementia, Fruits, Heart Disease, Stroke, Vegetables
Tagged as cancer, dementia, disease prevention, Fruits, heart disease, strokes, Vegetables
January 17, 2013 · 4:46 AM
Note the sugar cubes
The Mayo Clinic recently reported that diets high in carbohydrates and sugar increase the odds of developing cognitive impairment in the elderly years.
Mild cognitive impairment is usually a precursor to dementia. Many authorities think dementia develops more often in people with diabetes, although some studies refute the linkage.
Mayo investigators followed 940 patients with normal baseline cognitive functioning over the course of four years. Diet was assessed via questionnaire. Study participants were ages 70 to 89. As the years passed, 200 of them developed mild cognitive impairment.
Compared with those eating at the lowest level of carbohydrate consumption, those eating at the highest levels were almost twice as likely to go to develop mild cognitive impairment.
The scientists note that those eating lower on the carbohydrate continuum were eating more fats and proteins. Whether the Low-Carb Mediterranean Diet prevents cognitive impairments remains to be seen.
Steve Parker, M.D.
November 29, 2012 · 5:40 AM
“What about that recent study in American Journal of Clinical Nutrition…?”
As much as possible, I base my nutrition and medical recommendations on science-based research published in the medical literature. Medical textbooks can be very helpful, but they aren’t as up-to-date as the medical journals.
In the early 2000s, a flurry of research reports demonstrated that very-low-carb eating (as in Dr. Atkins New Diet Revolution) was safe and effective for short-term weight management and control of diabetes. I was still concerned back then about the long-term safety of the high fat content of Atkins. But 80 hours of literature review in 2009 allowed me to embrace low-carbohydrate eating as a logical and viable option for many of my patients. The evidence convinced me that the high fat content (saturated or otherwise) of many low-carb diets was little to worry about over the long run.
By the way, have you noticed some of the celebrities jumping on the low-carb weight-management bandwagon lately? Sharon Osbourne, Drew Carey, and Alec Baldwin, to name a few.
My primary nutrition interests are low-carb eating, the Mediterranean diet, and the paleo diet. I’m careful to stay up-to-date with the pertinent scientific research. I’d like to share with you some of the pertinent research findings of the last few years.
- Low-carb diets reduce weight, reduce blood pressure, lower triglyceride levels (a healthy move), and raise HDL cholesterol (another good trend). These improvements should help reduce your risk of heart disease. (In the journal Obesity Reviews, 2012.)
- Dietary fat, including saturated fat, is not a cause of vascular disease such as heart attacks and atherosclerosis (hardening of the arteries). (Multiple research reports.)
- If you’re overweight and replace two sugary drinks a day with diet soda or water, you’ll lose about four pounds over the next six months. (American Journal of Clinical Nutrition, 2012.)
- United States residents obtain 40% of total calories from grains and added sugars. Most developed countries are similar. Dr. Stephan Guyenet notes that U.S. sugar consumption increased steadily “…from 6.3 pounds [2.9 kg] per person per year in 1822 to 107.7 pounds [50 kg] per person in 1999. Wrap your brain around this: in 1822 we ate the amount of added sugar in one 12-ounce can of soda every five days, while today we eat that much sugar every seven hours.”
- A very-low-carb diet improves the memory of those with age-related mild cognitive impairment. Mild cognitive impairment is a precursor to dementia. (University of Cincinnati, 2012.)
- High-carbohydrate and sugar-rich diets greatly raise the risk of mild cognitive impairment in the elderly. (Mayo Clinic study published in the Journal of Alzheimers’ Disease, 2012.)
- Compared to obese low-fat dieters, low-carb dieters lose twice as much fat weight. (University of Cincinnati, 2011.)
- Diets low in sugar and refined starches are linked to lower risk of age-related macular degeneration in women. Macular degeneration is a major cause of blindness. (University of Wisconsin, 2011.)
- A ketogenic (very-low-carb) Mediterranean diet cures metabolic syndrome (Journal of Medicinal Food, 2011.)
- For type 2 diabetics, replacing a daily muffin (high-carb) with two ounces (60 g) of nuts (low-carb) improves blood sugar control and reduces LDL cholesterol (the “bad” cholesterol). (Diabetes Care, 2011.)
- For those afflicted with fatty liver, a low-carb diet beats a low-fat diet for management. (American Journal of Clinical Nutrition, 2011.)
- For weight loss, the American Diabetes Association has endorsed low-carb (under 130 g/day) and Mediterranean diets, for use up to two years. (Diabetes Care, 2011.)
- High-carbohydrate eating doubles the risk of heart disease (coronary artery disease) in women. (Archives of Internal Medicine, 2010.)
- One criticism of low-carb diets is that they may be high in protein, which in turn may cause bone thinning (osteoporosis). A 2010 study shows this is not a problem, at least in women. Men were not studied. (American Journal of Clinical Nutrition.)
- High-carbohydrate eating increases the risk of developing type 2 diabetes (American Journal of Clinical Nutrition, 2010.)
- Obesity in U.S. children tripled from 1980 to 2000, rising to 17% of all children. A low-carb, high-protein diet is safe and effective for obese adolescents. (American Journal of Clinical Nutrition, 2010.)
The traditional Mediterranean diet is well established as a healthy way of eating despite being relatively high in carbohydrate: 50 to 60% of total calories. It’s known to prolong life span while reducing rates of heart disease, cancer, strokes, diabetes, and dementia. The Mediterranean diet is rich in fresh fruits, vegetables, nuts and seeds, olive oil, whole grain bread, fish, and judicious amounts of wine, while incorporating relatively little meat. It deserves your serious consideration. I keep abreast of the latest scientific literature on this diet.
- Olive oil is linked to longer life span and reduced heart disease. (American Journal of Clinical Nutrition, 2012.)
- Olive oil is associated with reduced stroke risk. (Neurology, 2012).
- The Mediterranean diet reduces risk of sudden cardiac death in women. (Journal of the American Medical Association, 2011.)
- The Mediterranean diet is linked to fewer strokes visible by MRI scanning. (Annals of Neurology, 2011.)
- It reduces the symptoms of asthma in children. (Journal of the American Dietetic Association, 2011.)
- Compared to low-fat eating, it reduces the incidence of type 2 diabetes by 50% in middle-aged and older folks. (Diabetes Care, 2010.)
- A review of all available well-designed studies on the Mediterranean diet confirms that it reduces risk of death, decreases heart disease, and reduces rates of cancer, dementia, Parkinson’s disease, stroke, and mild cognitive impairment. (American Journal of Clinical Nutrition, 2010.)
- It reduces the risk of breast cancer. (American Journal of Clinical Nutrition, 2010.)
- The Mediterranean diet reduces Alzheimer’s disease. (New York residents, Archives of Neurology, 2010).
- It slows the rate of age-related mental decline. (Chicago residents, American Journal of Clinical Nutrition, 2010.)
- In patients already diagnosed with heart disease, the Mediterranean diet prevents future heart-related events and preserves heart function. (American Journal of Clinical Nutrition, 2010.)
Clearly, low-carb and Mediterranean-style eating have much to recommend them. Low-carb eating is particularly useful for weight loss and management, and control of diabetes, prediabetes, and metabolic syndrome. Long-term health effects of low-carb eating are less well established. That’s where the Mediterranean diet shines. That’s why I ask many of my patients to combine both approaches: low-carb and Mediterranean. Note that several components of the Mediterranean diet are inherently low-carb: olive oil, nuts and seeds, fish, some wines, and many fruits and vegetables. These items easily fit into a low-carb lifestyle and may yield the long-term health benefits of the Mediterranean diet. If you’re interested, I’ve posted on the Internet a Low-Carb Mediterranean Diet that will get you started.
Steve Parker, M.D.
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.
Filed under Carbohydrate, Fat in Diet, Health Benefits, Heart Disease, ketogenic diet, Mediterranean Diet, nuts, olive oil, Stroke, Vegetables, Weight Loss
Tagged as Atkins diet, dementia, diabetes, diet-heart hypothesis, dietary fat, healthy diet, heart attack, low-carb diet, low-carb diet research, macular degeneration, Mediterranean Diet, mild cognitive impairment, nutrition research, olive oil, paleo diet, saturated fat, Stroke