Image:
-
The Wisdom of Psychopaths
In this engrossing journey into the lives of psychopaths and their infamously crafty behaviors, the renowned psychologist Kevin Dutton reveals that there is a...
Read More »
Hara hatchi bu, the Okinawan people’s habit of eating only till they are 80 percent full, is thought to be one of the secrets of their extraordinary health and longevity. In addition to one of the highest percentages of people in the world who live past 100, Okinawans appear to be less prone to heart disease, diabetes and obesity.
Indeed, ever since it was discovered in the 1930s that laboratory rats fed a caloric-restricted (CR) diet lived almost twice as long as their well fed counterparts, scientists have pursued caloric restriction research in the hopes of finding novel strategies for extending human life and preventing disease. Given the growing older population at risk for memory problems and the rising rates of obesity, the role of diet in maintaining peak brain performance has taken on added importance.
Although the links between caloric restriction and longevity are still not fully proven in humans, short-term human trials have clearly shown that CR can improve many vital surrogate health markers, such as body weight, blood pressure, blood sugar and insulin levels, blood cholesterol and triglyceride levels, and measures of inflammation. High insulin levels and inflammation have both been linked to cognitive problems. In mice, reducing calories also promotes neurogenesis and slows certain Alzheimer’s-related changes in parallel with reductions seen in blood insulin and inflammation. Thus, there is great interest in examining the effects of CR on brain health in humans and in comparing its effects with those of other diets (for example, diets rich in healthier unsaturated fats) that may also help memory.
Diet and Memory
A recent study on caloric restriction and memory led by the neurologist Agnes Floel and her colleagues at the University of Munster took the first step in examining this issue. They recruited 50 older (ages 50 to 80 years) adults with a normal memory. Subjects on average were slightly overweight. The researchers assigned the volunteers to three groups, based on their age, gender and weight. Group 1 got a diet with 30 percent reduced daily calories and normal levels of other essential nutrients; the minimal level was set at 1,200 calories daily to prevent malnourishment. Group 2’s diet had 20 percent increased unsaturated fatty acids with no increase in total fat—thus boosting the ratio of healthy (unsaturated) to unhealthy (saturated) fats. The control was Group 3)—who had a diet as usual. None of the participants were advised to change their exercise habits. The researchers gave subjects in the first two groups individualized dietary plans and monitored their diet via self-reports. All subjects underwent memory and blood tests before and after the three months in the trial.
At the end of three months, the reduced-calorie diet group showed a small reduction in body weight (by 2.4 kilograms), whereas the other two diet groups showed a slight increase in weight (by about one kilogram). There was, however, a highly significant (about 20 percent above baseline) improvement in the CR group’s ability to recall words they had on a list (called delayed recall), and they also made fewer errors. Their memory improvement tended to be correlated with reductions in blood insulin and markers of inflammation (C-reactive protein and TNF-alpha). Memory did not change in the other two diet groups.
This study is commendable because it is the first prospectively planned trial in older adults to demonstrate memory benefits of a low-calorie diet. The replication in humans of some of the findings seen in earlier animal studies provides an important proof of concept step that will encourage and guide the design of larger future studies. Further, it demonstrated improvements in the type of memory (delayed recall) that is typically the first to fail in very early stages of Alzheimer’s disease.
See what we're tweeting about
17 Comments
Add CommentOh great, now my wife will really be on me to start that diet *chuckle* Rather ironic that the "less is more" theory seems to have some biological benefit.
Reply | Report Abuse | Link to thisIf Calorie Restriction were a proprietary drug, it would have already been subject to a huge marketing blitz claiming it is the new "miracle drug", virtual "cure all".
Reply | Report Abuse | Link to thisThink they tried that with the push to eat fiber before each meal? It too failed.
Reply | Report Abuse | Link to thisThe answers to most of the questions asked at the end of the article can be found at www.calorierestriction.org . I have been eating a calorie restricted diet (from an initial 2500 down to 1800 calories) for about 10 years. I lost 25 lb before my weight stabilized. My vitality and memory improved and, at age 62, I do not plan on going back to the SAD (standard American diet). In a life not exactly filled with great decisions, my CR adventure, as I call it, was a great one!
Reply | Report Abuse | Link to thisAfter my rollercoaster weight gaining and my heart scare, I went on a bean, potato, lean meat, and no sugary desert diet and knocked off 30 pounds and kept it off now for eight years. But I found the best diet you can be on is to stay away from fast greasy food restaurants. Only eat at restaurants that have a high variety salad bar and serve sea salt as a flavor enhancer.
Reply | Report Abuse | Link to thisHara hatchi bu.
Reply | Report Abuse | Link to thisAll Japanese know this phrase. Why they confined to only "Okinawan".
I have been eating more calories and then using exercise to burn them off such that my net calorie count is similar to the diet above. I wonder if the benefits would be the same as not exercising down to an acceptable net count.
Reply | Report Abuse | Link to thisI wonder if you get the same effect if you burn down the net daily calorie count with exercise?
Reply | Report Abuse | Link to this@kgp10ec In my experience, that is true. Net caloric intake is the key factor. If one follows a restricted diet, the final daily number should be the 30% reduction. Otherwise, one could never exercise since it would dangerously reduce the energy balance.
Reply | Report Abuse | Link to this[expanded from Twitter thread] @Sciam This reveals an example of the dichotomy of stress; moderate physical stress can enhance health while mental stress takes it's toll on both brain and body. There is evidence suggesting that mental stress enhancing levels of circulating stress hormones) can trigger signaling pathways that lead to learning and memory defects in rodents.
Reply | Report Abuse | Link to thisTotally agreed with you...
Reply | Report Abuse | Link to thisActually it's very easy to stay away from those greasy fatty food. Don't try to eat at those restaurants if you don't have to. Buy the necessary ingredients and cook them in your home. Prepare your own food by yourself and see what and how much you're putting in. That's the best way to stay healthy, if you want so :)
Reply | Report Abuse | Link to thisMaybe it is not is not only the calorie restriction. I am mother of a 16 yrs old disabled girl. She has refractory epilepsy and been on a very restricted ketogenic diet now for over a year. This has helped her epilepsy and she has been growing as never before, whilst on very low calories. Her brain is certainly doing better burning on ketones instead of glucose. Mind you this diet is not some complementary humbug, but a strictly medically. supervised treatment. Most children on this diet do not grow very well, but she certainly has been an acception, going into puberty growth spurt right after we started this diet.
Reply | Report Abuse | Link to thisMaybe it is not is not only the calorie restriction. I am mother of a 16 yrs old disabled girl. She has refractory epilepsy and been on a very restricted ketogenic diet now for over a year. This has helped her epilepsy and she has been growing as never before, whilst on very low calories. Her brain is certainly doing better burning on ketones instead of glucose. Mind you this diet is not some complementary humbug, but a strictly medically. supervised treatment. Most children on this diet do not grow very well, but she certainly has been an acception, going into puberty growth spurt right after we started this diet.
Reply | Report Abuse | Link to thisMaybe it is not is not only the calorie restriction. I am mother of a 16 yrs old disabled girl. She has refractory epilepsy and been on a very restricted ketogenic diet now for over a year. This has helped her epilepsy and she has been growing as never before, whilst on very low calories. Her brain is certainly doing better burning on ketones instead of glucose. Mind you this diet is not some complementary humbug, but a strictly medically. supervised treatment. Most children on this diet do not grow very well, but she certainly has been an acception, going into puberty growth spurt right after we started this diet.
Reply | Report Abuse | Link to thisMaybe it is not is not only the calorie restriction. I am mother of a 16 yrs old disabled girl. She has refractory epilepsy and been on a very restricted ketogenic diet now for over a year. This has helped her epilepsy and she has been growing as never before, whilst on very low calories. Her brain is certainly doing better burning on ketones instead of glucose. Mind you this diet is not some complementary humbug, but a strictly medically. supervised treatment. Most children on this diet do not grow very well, but she certainly has been an acception, going into puberty growth spurt right after we started this diet.
Reply | Report Abuse | Link to thisMaybe it is not is not only the calorie restriction. I am mother of a 16 yrs old disabled girl. She has refractory epilepsy and been on a very restricted ketogenic diet now for over a year. This has helped her epilepsy and she has been growing as never before, whilst on very low calories. Her brain is certainly doing better burning on ketones instead of glucose. Mind you this diet is not some complementary humbug, but a strictly medically. supervised treatment. Most children on this diet do not grow very well, but she certainly has been an acception, going into puberty growth spurt right after we started this diet.
Reply | Report Abuse | Link to this