Archive for the ‘Nutrition’ Category
It has been suggested that nutrition may play a role in age-related hearing loss and that it may be associated with poor micronutrient status. For example, Vitamin B-12 or folate deficiencies may negatively influence blood flow to the cochlea, leading to age-related hearing loss. Australian researchers showed that people with hearing loss were more likely to be exposed to workplace noise, be a current smoker, have a doctor-diagnosed history of stroke or type 2 diabetes, and to have Vitamin B-12 (1).
In Finland, two groups of 40-59-year olds were studied, 1) one on a diet high in saturated animal fats, 2) the other on a diet high in polyunsaturated fats. After 5 years of follow up, blood vessel condition was better in the group 2 and the participants hearing ability was also significantly better in all frequencies. After that, the diets in the two groups were reversed. Four years after the diet reversal the hearing in the now low-fat group was improved and the hearing in the now high-fat group was deteriorating. The authors concluded that a diet high in polyunsaturated fats may stop, if not reverse, hearing loss (2).
In a recent Dutch study, 720 participants 50–70 years of age without hearing loss were tested for levels of polyunsaturated fats, very long-chain n-3 PUFA in their plasma. In high sound frequencies, there was no correlation of hearing acuity and PUFA concentrations in plasma. However, in the low frequencies, the higher PUFA levels corresponded to better hearing abilities. The authors found their results “encouraging, but requirig confirmation from future studies.” (3)
Serum Homocysteine and Folate Concentrations Are Associated with Prevalent Age-Related Hearing Loss. Journal of Nutrition, Vol. 140, No. 8, 1469-1474, Aug, 2010
DIETARY PREVENTION OF HEARING LOSS. Acta Otolaryng 70: 242-247, 1970
PLASMA VERY LONG-CHAIN N-3 POLYUNSATURATED FATTY ACIDS AND AGE-RELATED HEARING LOSS IN OLDER ADULTS. THE JOURNAL OF NUTRITION, HEALTH & AGING Volume 14, Number 5, 347-351, 200
It has been suggested that nutrition may play a role in age-related hearing loss and that it may be associated with poor micronutrient status. For example, Vitamin B-12 or folate deficiencies may negatively influence blood flow to the cochlea, leading to age-related hearing loss. Australian researchers showed that people with hearing loss were more likely to be exposed to workplace noise, be a current smoker, have a doctor-diagnosed history of stroke or type 2 diabetes, and to have Vitamin B-12 (1).
In Finland, two groups of 40-59-year olds were studied, 1) one on a diet high in saturated animal fats, 2) the other on a diet high in polyunsaturated fats. After 5 years of follow up, blood vessel condition was better in the group 2 and the participants hearing ability was also significantly better in all frequencies. After that, the diets in the two groups were reversed. Four years after the diet reversal the hearing in the now low-fat group was improved and the hearing in the now high-fat group was deteriorating. The authors concluded that a diet high in polyunsaturated fats may stop, if not reverse, hearing loss (2).
In a recent Dutch study, 720 participants 50–70 years of age without hearing loss were tested for levels of polyunsaturated fats, very long-chain n-3 PUFA in their plasma. In high sound frequencies, there was no correlation of hearing acuity and PUFA concentrations in plasma. However, in the low frequencies, the higher PUFA levels corresponded to better hearing abilities. The authors found their results “encouraging, but requirig confirmation from future studies.” (3)
- Serum Homocysteine and Folate Concentrations Are Associated with Prevalent Age-Related Hearing Loss. Journal of Nutrition, Vol. 140, No. 8, 1469-1474, Aug, 2010
- DIETARY PREVENTION OF HEARING LOSS. Acta Otolaryng 70: 242-247, 1970
- PLASMA VERY LONG-CHAIN N-3 POLYUNSATURATED FATTY ACIDS AND AGE-RELATED HEARING LOSS IN OLDER ADULTS. THE JOURNAL OF NUTRITION, HEALTH & AGING Volume 14, Number 5, 347-351, 200
According to this review, a simple dietary change towards lower carbohydrate intake and higher fats intake, may be efficiently protective against AD. >> read the article
How can calorie restriction improve brain function
Researchers at the Internal Medicine & Gerontology and INSERM, Toulouse, France pointed to an array of ways that hopefully can lead to real managing of age-related diseases of the brain. They all concern calorie restriction. Thus, according to the review published by the Current Opinion in Clinical Nutrition and Metabolic Care, calorie restriction (CR) can protect the brain by the following mechanisms:
1. It’s a new way to improve brain health via induction of neurogenesis
2. It affects the risk for neurodegenerative disorders by increasing resistance to oxidative, metabolic or excitotoxic injuries
3. It results particularly in the upregulation of the brain-derived neurotrophic factor (BDNF) in hippocampal and cortical neurons of rats and mice, which may protect neurons against excitotoxic, oxidative and metabolic insults
4. It may prevent beta-amyloid neuropathology
5. It promote neuronal plasticity
The authors conclude: “It is now well established that caloric restriction could be used to promote successful brain aging. Data from randomized controlled trials in humans are limited. No positive effect on cognitive impairment was found probably due to methodological limitations. The long-term effects of caloric restriction in adults must be clarified before engaging in such preventive strategy. Additional animal studies must be conducted in the future to test the effects of ‘multidomain’ interventions (caloric restriction plus regular exercise) on age-related cognitive decline”
Source:
S. Gillette-Guyonneta, and B. VellasaCaloric restriction and brain function. Current Opinion in Clinical Nutrition and Metabolic Care 2008, 11:686–692
Researchers at the Internal Medicine & Gerontology and INSERM, Toulouse, France pointed to an array of ways that hopefully can lead to a real management of age-related diseases of the brain. They all concern calorie restriction. Thus, according to the review published by the Current Opinion in Clinical Nutrition and Metabolic Care, calorie restriction (CR) can protect the brain by the following mechanisms:
1. It’s a new way to improve brain health via induction of neurogenesis
2. It affects the risk for neurodegenerative disorders by increasing resistance to oxidative, metabolic or excitotoxic injuries
3. It results particularly in the upregulation of the brain-derived neurotrophic factor (BDNF) in hippocampal and cortical neurons of rats and mice, which may protect neurons against excitotoxic, oxidative and metabolic insults
4. It may prevent beta-amyloid neuropathology
5. It promotes neuronal plasticity
The authors conclude: “It is now well established that caloric restriction could be used to promote successful brain aging. Data from randomized controlled trials in humans are limited. No positive effect on cognitive impairment was found probably due to methodological limitations. The long-term effects of caloric restriction in adults must be clarified before engaging in such preventive strategy. Additional animal studies must be conducted in the future to test the effects of ‘multidomain’ interventions (caloric restriction plus regular exercise) on age-related cognitive decline”
Source:
S. Gillette-Guyonneta, and B. VellasaCaloric restriction and brain function. Current Opinion in Clinical Nutrition and Metabolic Care 2008, 11:686–692
Research results showed that when calories are restricted in older animals, an increase in life span is still observed; though not as great as that observed in the animals that were calorie restricted since they were young. The data of this research suggests there may be a level of maturity, or a stage in the aging process, after which caloric restriction no longer increases longevity. (6) Restricted nutrient intake may have beneficial effects on alults’ degenerative disease, autoimmune processes, susceptibility to infection and survival rate after infection. (New Horizons, 2(2):257-63, 1994).
Adult rats fed the calorie restricted yet nutritionally balanced diet ate fewer meals but consumed more food during each meal. They also spent more time eating during each meal. The average body temperature per day was significantly lower in restricted rats. However, they moved around significantly more than the rats that were fed as much as they pleased, so they spent more energy during the day.
Veldhors and colleagues at Maastricht University, Netherlands, compared the effects of a high- (HP) and normal-protein (NP) breakfast on satiety and subsequent energy intake at lunch time. Casein was the only source of protein during breakfast to eliminate the influence of different amino acid composition. They reported that:
1. Taste perception, hedonic, and reward properties of the pretest brekfast did not differ for HP and NP.
2. Insulin and glucose was higher after NP in less than 1 hour. Satiety (3 and 4 hours after breakfast) and fullness (less than 1 hour) were higher after HP. Energy intake at lunch did not differ after HP versus NP.
The present study shows that a breakfast with 25% of energy from casein is rated as being more satiating than a breakfast with 10% of energy from casein at 3 and 4 h after breakfast, coinciding with prolonged elevated concentrations of plasma amino acids, but does not reduce subsequent energy intake.
Veldhors and colleagues at Maastricht University, Netherlands, compared the effects of a high- (HP) and normal-protein (NP) breakfast on satiety and subsequent energy intake at lunch time. Casein was the only source of protein during breakfast to eliminate the influence of different amino acid composition. They reported in British Journal of Nutrition (2009, 101, 295–303 ) that:
1. Taste perception, hedonic, and reward properties of the pretest brekfast did not differ for HP and NP.
2. Insulin and glucose was higher after NP in less than 1 hour.
3. Satiety (3 and 4 hours after breakfast) and fullness (less than 1 hour) were higher after HP.
4. Energy intake at lunch did not differ after HP versus NP.
“The present study shows that a breakfast with 25% of energy from casein is rated as being more satiating than a breakfast with 10% of energy from casein at 3 and 4 h after breakfast, coinciding with prolonged elevated concentrations of plasma amino acids, but does not reduce subsequent energy intake,” concluded the authors.
I calculated the ketogenic ratios of the pretest breakfasts. They both turned out to be below the ketogenic threshold, which is 1:2 according to the Wilder & Winter formula: 1:0.418 for NP and 1:0.565 for HP, which means that both breakfasts helped the carbohydrate but not fat metabolism. How the switch to the fat metabolism due to higher ketogenic ratios at breakfast influences metabolic and psychological parameters during the day, is a different story.
“The Atkins Nutritional Approach counts grams of carbohydrates instead of calories… If you are losing weight, there is no need to concern yourself with counting calories. ”
Source: atkins.com
What you sometime read about low carb diets may make you doubtful. For example, here’s an opinion posted by “Health Care Reality Check”:
Q: Can a person eat unlimited calories, and still lose weight, as long as they severely restrict carbohydrates?
A: No, she can not. The basis of ketogenic diets, such as the Atkins Diet, is a severe restriction of carbohydrate calories, which simply causes a net reduction in total calories. Since carbohydrate calories are limited, intake of fat usually increases. This high fat diet causes ketosis (increased blood ketones from fat breakdown), which suppresses hunger, and thus contributes to caloric restriction. — Ellen Coleman, RD, MA, MPH
Is this a correct answer?
Let’s first discuss whether it’s a correct question. Or, rather, is this the real question so frequently asked by dieters. In my experience, this in fact sounds a little bit different but this makes ALL the difference.
This is what real dieters ask:
Q: Can low carb dieters eat all they want, and still lose weight as long as they only eat allowed foods?
A: Yes, they can. The basis of ketogenic diets, such as the Atkins Diet, is a restriction of carbohydrate-containing foods in favor of fat and protein containing foods, which causes the state of ketosis resulting in significant decrease in appetite. Since appetite decreases, most of low carb dieters consume significantly less calories WITHOUT INTENTIONAL CALORIE RESTRICTION.
Is there scientific evidence? There is.
Study #1 by: Bassett Research Institute in Cooperstown, NY and Durham (N.C.) Veterans Affairs Medical Center.
Reported: Proceedings of North American Association for the Study of Obesity, Oct. 29, 2000, Long Beach, CA
Who participated:
- 18 obese men and women with 30 or more pounds to lose.
- Average calorie intake before the study: 2,481 calories a day
Method:
Dr. Atkins’ Book, the “New Diet Revolution” used as instruction for the dieters.
Results:
1. Calorie intake during the most restrictive induction phase (when only 20 g of carbohydrates were allowed) was 1,419 calories a day on average and weight loss was more than 8 pounds on average.
2. Calorie intake during the ongoing weight-loss phase (when carbohydrate intake is being increased gradually, by 5 g a day) dieters ate an average of 1,500 calories a day and lost an additional 3 pounds in two weeks.
3. The calorie reduction was attributed almost completely to carbohydrate abstaining. Intake of fat and protein remained practically the same as before the diet.
4. After 6 months on Atkins diet, 41 overweight people lost an average of 10% of their weight. Most dieters lowered their cholesterol by 5%, but there were a few whose cholesterol increased.
5. 20 out of 41 dieters continued the program, and kept the lost weight off for more than a year.
Study #2 by: Harvard School of Public Health.
Reported: American Association for the Study of Obesity, October 16, 2003
Who participated: 21 overweight volunteers.
- Two groups were randomly assigned to either lowfat or low-carb diets with 1,500 calories for women and 1,800 for men; a third group was also low-carb but got an extra 300 calories a day.
Method:
All the food was prepared at a restaurant in Cambridge, Massachusetts. Note that most earlier studies including the above Study #1 simply gave out diet plans.
So in this study, dieters were given dinner and a bedtime snack as well as breakfast and lunch for the next day, which made the setting a carefully controlled one. Foods were mostly fish, chicken, salads, vegetables and unsaturated oils. Red meats and saturated fats were limited (as opposed to traditional Atkins menus.)
All meals looked similar but were cooked to different recipes. The low-carb meals were 5% carbs, 15% protein, 65% fat. The low fat group got 55% carbohydrate, 15% protein, 30% fat.
Results:
1. All dieters lost weight, but those on low carb diet lost more than the low fat group — even while consuming MORE calories:
- Group on lower-cal, low-carb diet lost an average of 23 lbs.
- Group on same-calories low-fat diet lost an average of 17 lbs.
- Group on extra 300 calories, low-carb diet lost an average of 20 lbs.
2. Over the course of the study, the group of low carb dieters who got an extra 300 calories a day consumed extra 25,000 calories. That should have added up to about seven pounds. But for some reason, it did not.
Discussion:
“It doesn’t make sense, does it?” said Barbara Rolls of Pennsylvania State University. “It violates the laws of thermodynamics. No one has ever found any miraculous metabolic effects.”
So it violates the laws of thermodynamics, huh? Not so fast! When it comes to calorie counting, the “calorie is a calorie” concept is very deceiving.
Let’s see what we count when we think we count calories. When you burn a piece of wood in a stove, you can directly measure how much heat energy it produces. Then you can claim that you know how many calories a piece of wood contains, right? Not exactly. You should specify what kind of wood it was, dry or wet, how you burned it, etc. Because if you spent another material to start the burning, you should subtract these calories from the total; if the wood was wet you should take into account the calories that the water evaporation took. So even with a piece of wood, it’s not that simple.
Now look at a piece of food. You know how they tell how many calories it contains? Same way they talk about a piece of wood in a stove. It’s the calorie number that the food would produce by being burnt in a stove.
Then in addition to the wood’s calorie estimation (that takes into account the dryness, etc.), you should add many more circumstances: how hard should one chew it before being able to swallow, how hard one’s enzyme system will have work to digest it, will it influence the hormones in charge of fat storing? What about its effect on the hormones in charge of fat burning?
Which chain of reactions will it trigger, activity-wise or metabolism-wise? Will it make one sleepy, thus conserving the energy? Ot will it make one jumpy, thus wasting the energy?
Study #3 by: Laboratory of Applied Physiology, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan
Reported: J Clin Endocrinol Metab. 2003 Dec;88(12):5661-7
Method:
Healthy boys, aged 8-11 yr, were examined for resting energy expenditure and the thermic effect of a meal, which were measured for three hours after a same-calorie but high-fat or a high-carb meals.
Results:
There was no changes after high carbohydrate meals but there was an increase in resting energy expenditure after a high-fat meal.
If the researchers in the Study #2 would have measured resting energy expenditure and the thermic effects of the meals, they would probably have registered the same changes. Then everybody would make a sigh of relief: none of the laws of thermodynamics have been violated; yes, the low-carb dieters COULD INDEED eat more calories and lose more weight than the low-fat group while violating no physical laws because — they just burnt more, all the time, even at rest. It’s that simple.
There is plenty of anecdotal evidence that after about one week on a low carbohydrate diet, mood and energy levels go through the roof. Researchers speculate that this can be explained by interplay of brain chemicals after the brain stops running on glucose and switches on ketons for fuel.
The brain is the organ most sensitive to a change in blood glucose level – too little produces fatigue, confusion, irritability and aggression. Decreased glucose sensitivity often develops due to excessive consumption of refined sugar and simple carbohydrates, like in white flour. When the brain adapts to the use of ketones instead glucose, these symptoms disappears.
A low-fat diet may be good for your body, but not necessarily for your mind. In a study at Wake Forest University, researchers found that monkeys on a low-fat diet were more hostile than monkeys that were fed foods high in fat. It is though that lower cholesterol decreases levels of serotonin and weakens emotional control.
Low fat diets can make you depressed. Research has linked diets that drastically cut down on all types of fat with an increase in symptoms of depression. Study conducted by University of Sheffield, demonstrated that meals rich in fat, significantly reduced pain perception in healthy human subjects (Physiology & Behavior. 65(4-5):643-8, 1999)
Thirty percent less calories equals thirty percent better memory
Calorie restriction benefits for the aging brain health have been proposed and the mechanisms were suggested but a direct evidence showing that it can improve memory function in elderly humans appeared only recently. The study conducted in Munster, Germany, showed that a three months calorie intake reduction by 30% compared with habitual diet or a Mediterranean style diet rich in unsaturated fatty acids (although known to positively influence memory) resulted in a highly significant, 30% improvement in memory scores of 60 something group of relatively healthy people.
A. Witte et al., 2009. Caloric restriction improves memory in elderly humans. PNAS, vol. 106 no. 4 1255–126
Calorie restriction benefits for the aging brain health have been proposed and the mechanisms were suggested but a direct evidence showing that it can improve memory function in elderly humans appeared only recently. The study conducted in Munster, Germany, showed that a three months calorie intake reduction by 30% compared with habitual diet or a Mediterranean style diet rich in unsaturated fatty acids (although known to positively influence memory) resulted in a highly significant, 30% improvement in memory scores of 60 something group of relatively healthy people.
A. Witte et al., 2009. Caloric restriction improves memory in elderly humans. PNAS, vol. 106 no. 4 1255–126
Any restrictive diet can cause depression sometime called diet blues. For people on a low fat diet a quick fix can be a carbohydrate-containing snack – a fruit or a hard candy. For people on the initial stages of low carbohydrate diets a quick fix is completely different. Turkey and chicken contain a good source of mood-enhancer tryptophan, an amino acid which is a raw material for serotonin – which can be low in people suffering from depression. Poorly eating and sleep habits can negatively influence otherwise normal serotonin levels.
A low-fat diet may be good for your body, but not necessarily for your mind. In a study at Wake Forest University, researchers found that monkeys on a low-fat diet were more hostile than monkeys that were fed foods high in fat. It is though that lower cholesterol decreases levels of serotonin and weakens emotional control.
Low fat diets can make you depressed. Research has linked diets that drastically cut down on all types of fat with an increase in symptoms of depression.
There is plenty of anecdotal evidence that after about one week on a low carbohydrate diet, mood and energy levels go through the roof. Researchers speculate that this can be explained by interplay of brain chemicals after the brain stops running on glucose and switches on ketons for fuel.
The brain is the organ most sensitive to a change in blood glucose level – too little produces fatigue, confusion, irritability and aggression. Decreased glucose sensitivity often develops due to excessive consumption of refined sugar and simple carbohydrates, like in white flour. When the brain adapts to the use of ketones instead glucose, these symptoms disappears.
Study conducted by University of Sheffield, demonstrated that meals rich in fat, significantly reduced pain perception in healthy human subjects.( Physiology & Behavior. 65(4-5):643-8, 1999)
