Less Calories Better Memory?
January 30, 2009
There is a scientific argument raging about whether restricting calorie intake in humans has any health benefits or not. Another study that adds to the fray suggests less calories leads to a better memory.
It is clear in mice that calorie restriction leads to a longer life and a reduction in the diseases of aging such as heart disease. However, in humans the picture is not clear. Part of the problem is that it hard to get most humans to significantly restrict their food intake for long periods of time.
A new study suggests that cutting back on calories may improve memory. Participants in the study were normal to overweight, with a mean age of 60.5 years. They were divided into three groups. One group cut their calories by 30%, relative to what they had been eating before (mainly by smaller portion sizes), a second group increased the amount of unsaturated fats by 20%, reducing their intake of saturated fat so that total fat intake did not change, and the third group made no dietary changes.
All participants were tested at the start of the study and three months later. Only those on the calorie restricted diet showed an increase in verbal memory scores. They were tested for working memory, attention and delayed memory. The delayed memory test involved learning as many words as possible from a list of 15 and then seeing how many could be recalled 30 minutes later.
Interestingly, increases in memory correlated with a decrease in levels of both fasting insulin and hsCRP. Decreased fasting insulin indicates a greater insulin sensitivity, which means better control of blood glucose. hsCRP is an indicator of inflammation and is used as a marker for increased risk of atherosclerosis (hardening of the arteries), with higher levels being used as an indicator of risk of cardiovascular disease. This suggests that lower levels of inflammation may be good for memory and that for some reason insulin sensitivity may be related to memory.
Other studies in humans have not shown any changes in memory ability with calorie restriction, but as usual all studies are small and they used younger study populations, were done in different ways with different testing.
If calorie restriction really is good for your health, the problem is how to eat less. I would like to see a big study in humans that looks at the effects of periodic short fasts on memory. A study in mice showed that memory is improved on a fasting regime. It has been shown in humans that fasting improves insulin sensitivity and cardiovascular health (see the post Occasional Short Fasts May Be Healthy), so it may help memory too. Most people find it easier to not eat for most or of a day (without compensating by eating a lot when having the first meal) rather than cut back all the time.
It is food for thought!
photo credit: Jacob Bøtter
Technorati Tags: calories, memory, fasts, fasting, calorie restriction, insulin hsCRP
Do You Have Diabetes?
January 28, 2009
There are some sobering numbers in an analysis of 2005–2006, the National Health and Nutrition Examination Survey (NHANES). The most shocking was that in adults, aged 20 years or older, that 40% are either pre-diabetic or diabetic. Plus 40% of those that have full blown diabetes do not know that they have it. So, do you have diabetes?
The number of persons with pre-diabetes or diabetes increases as we age. For the elderly (?) the prevalence of pre-diabetes and diabetes is about 75%. About a third of the elderly have diabetes.
These numbers are alarming since having uncontrolled diabetes has major health impacts. For instance it can cause retinopathy, resulting in a permanent reduction in ability to see. Diabetes is the leading cause of blindness in adults. Diabetes is associated with having an increased risk of having a heart attack, a stroke and whole range of other diseases.
Other findings were that number of people diagnosed diabetes has increased since the last survey. The epidemic of diabetes continues. Diabetes is more common in the Hispanic population than blacks or whites, but it is high in all populations.
current guidelines indicate that everybody 45 and older, or under 45 with one or more risk factors, should be have their glucose tested. Risk factors include family history of diabetes, being overweight, high triglycerides, low HDL (good) cholesterol, high blood pressure and being inactive. These risk factors cover most of the population! We all need to get tested at regular intervals.
The value of regular testing was just brought home to me recently. A person who works across the hall from me, who had not been tested in a long while, got a fasting glucose as part of health fair. It was high, he went to see his primary care physician who confirmed the test, and then gave him some medication. At the next physicians visit, his fasting glucose having been taking metformin (glucophage) for two months, was 320 mg/dl. (100 – 125 mg/dl is considered prediabetic, and 126 mg/dl and above, is diabetic.) He is now injecting himself with insulin. With regular testing, he would have been diagnosed sooner and been able to at least slow the progression of the diabetes, and certainly not have so much damage to his body from an extended period of high glucose.
It is worth finding out if you have diabetes.
photo credit: woody1778a
Technorati Tags: diabetes, pre-diabetes, NHANES
Get A Female Cardiologist?
January 26, 2009
A new study that looked at heart failure found that your gender affects your treatment. Besides the gender of the patient, the gender of the treating physician also affected treatment. The latter finding is quite surprising, at least to me.
It is probably no big surprise to anyone, that generally, men get more comprehensive treatment than females. This seems to be particularly true for diseases that have to do with the cardiovascular system.
In this new study, treatment of patients with heart failure was evaluated. There are guidelines in place in both the US and Europe that list specific medication categories for patients with certain sets of symptoms (i.e. different classifications). The study showed that males were much more likely to be given the medication, or medications, recommended in the guidelines. Women often got less medication than recommended in the guidelines.
The data shows that many women are undertreated, and their heart failure is not as well controlled as it is for men. It is estimated in that perhaps 1 in 10 of those over 65 years has heart failure. Statistics suggest that heart failure is one of the most common reasons for sudden hospitalization, and this costs the US 35 billion dollars a year. The medications used for treatment are not expensive, so besides moral considerations of undertreatment, a lot of money could be saved.
The surprising finding was that female physicians were much more likely than male physicians to give patients the medications suggested by the guidelines. Male physicians tended to have more patients who were under medicated. If I want to be snarky, this could be due to the arrogance that seems to be associated with male cardiologists. As a group they tend to have big egos and know everything. Perhaps the (few) women in the profession are more thoughtful and not so ego driven.
This study suggests two things. The first is that if you, or somebody you know, has heart failure make sure you get the correct medication(s). Ask your physician for your classification (often New York Association Functional Classification) and ask to be treated according to the guidelines for that classification.
Second, maybe when you need a cardiologist, you should think about going to a female cardiologist?
Technorati Tags: female cardiologist, gender, man, woman, male, female, heart failure, undertreatment, physician
Osteoporosis Round Up
January 23, 2009
Eating lots of vegetables may decrease the rate of osteoporosis (age-related bone loss).
Osteoporosis, age-related loss of bone mass, is a fact of aging. It is going to happen. However, there are steps you can take to slow the rate of loss. One of these is weight bearing exercise. Another may be eating lots of vegetables. It is suggested that antioxidants and other substances in vegetables and fruits may be good for your bones and hence slow the loss of bone. Another reason to eat your veggies.
Depression may have a link to osteoporosis
There may be a link between mental illness, especially depression and osteoporosis. A review of publications from 1994 to 2007 indicates that depression may accelerate bone loss. Depression has effects on the body including altering the function of both the immune and endocrine (hormone) systems. it is suggested that these changes in the immune and endocrine systems may have negative effects on the bone, leading to faster loss. Another reason to seek help for depression.
Osteoporosis may be detected at the dentist
A series of studies (example) has shown that dental x-rays can be used for detecting osteoporosis. DXA, the standard method of measurement of bone density, was compared to the use of software that measured thickness of jaw bones in regular dental x-rays. It was demonstrated that dental x-rays were a good predictor of osteoporosis. Hopefully this will soon be part of the standard analysis of dental x-rays. If we are going to get subjected to x-rays, we should get the max benefit from the exposure.
Technorati Tags: osteoporosis, age-related bone loss, vegetable, depression, dentist, dental x-rays
Do the microbes in your gut make you obese?
January 21, 2009
One of the mysteries of the human race, is why it so hard to lose weight. For some people the answer looks obvious, whether they acknowledge it or not, they are eating way too many calories. However, for other people it is harder to figure out why they find it so hard to lose weight, and really difficult to maintain any weight loss.
One new avenue of research suggests that the microbes that you have in your gut make you obese.
An older explanation, for this weighty problem, suggested a few years ago, is that in obese people metabolism slows down. This slower metabolism would mean that you would need to eat even less food than somebody who was “normal” weight to maintain weight. Further this means to lose weight very few calories per day would be needed.
The new research suggests, in those that are obese, that microbes in their guts are more efficient at extracting energy from food. Our intestines are full of different microbes. We have what is called a symbiotic relationship with most of them. They help digest our food and extract nutrients, inactivate some harmful compounds such as toxins and even make some nutrients such as vitamin K. They also help with our immune systems and may help fight off bad microbes from our food. In return the microbes have a protected environment and a continuous food source. So both us and the microbes benefit.
If obese people have microbes that can extract energy more efficiently this would mean that those with obesity would effectively get more calories from the same food than somebody who is not obese. This could be another reason it is hard to maintain weight, let alone lose it.
In the study there were three groups of people those who were not obese, those who were obese and those that had been obese but had had gastric bypass surgery. Those who were not obese and those that had lost weight due to the surgery had a different microbial profile than those that were obese. The good news is that those that had had the surgery and lost weight had the same profile as those that were not obese. This suggests that the profile can change, so with significant weight loss you may be able to revert to having less efficient microbes in your gut, and then actually need more calories to put on weight. More information about the study.
If either or both the slower metabolism and gut microbe theories are both correct, this would help explain why is so very hard to lose and weight. Life is sometimes not fair.
photo credit: davitydave
Technorati Tags: microbes, gut, energy efficient, obese
Exercise – Yes We Can
January 19, 2009
It is estimated that one in four adult Americans are sedentary. They do not do any exercise at-all. Many will say that they do not have the time, the ability or the knowledge to start to exercise. Starting to get some or more exercise is not difficult. So in the spirit of the inauguration; Exercise – Yes We Can. – You can do it.
I am going to highlight two studies, one that is almost exactly 10 years old, and one that is new.
In the older study at the Cooper Institute, study participants that were sedentary were divided into groups. One group was placed in an exercise program and general behavioral advice, and the other group was given personalized guidance as to how to increase their physical activity. The personalized guidance was simple changes to lifestyle, which that increased the amount of activity in doing everyday things.
After 2 years both groups had increased their physical exercise and had improved their blood pressure and cardiovascular fitness. This research shows that simple changes in the way you do daily activities can increase the level of exercise and have positive changes in your health. It shows that it is not necessary to be totally gung ho and go to the gym or whatever, to get more exercise. Find some simple things you can do.
The recent study showed that those who thought they had thought they had the ability to do exercise were more likely to do it. This sounds really obvious, but it has consequences. If you try some exercise and find that you can do it, then you are more likely to do it. So go and try some things. There is not much to lose but a lot to be gained. You can do it.
photo credit: elana CXLIV
Technorati Tags: exercise, physical activity, yes we can, si se puede
Avocado Oil – An Oil You Should Consume?
January 15, 2009
One of the newest trends in oil is avocado oil. Recently, avocados have been listed as a “super food” in many articles. Avocado oil has some great features, so think about including it in your diet.
I was in a local supermarket a few weeks before Christmas, saw avocado oil and bought some to see what it was like. The oil I bought is a thick light yellow green color and has a mild flavor. To me it didn’t really taste like avocados, it had a flavor of its own. I thought it was very pleasant. I prefer the taste of olive oil, but then I am used to eating olive oil. Interestingly, unlike most other oils, the oil is extracted from the flesh not the seed.
Avocado oil, like olive oil, is high in monounsaturated fats. So it is thought to have some similar health benefits to olive oil. There are three differences between avocado and olive oils, which might make you want to use it as well as olive oil.
First, avocado oil (and avocados) contain beta-sitosterol, a natural reducer of levels of cholesterol. It used to be recommended by some physicians for treatment of high cholesterol, but the introduction of drugs such as statins which will lower cholesterol more, has led to it being out of favor. Beta-sitosterol is also found in saw palmetto, pumpkin seeds and soybeans. There is some evidence that beta-sitosterol may have positive effects on benign prostatic hypertrophy (non cancerous increase in the size of the prostate, leading increased frequency and urgency of urination).
Second, avocado oil is a good source of vitamin E.
Third, avocado oil has a very high smoke point. Different sources assign different temperatures, but the smoke point is probably at least 500 oF, which is higher than most other oils and considerable higher than olive oil. The smoke point of an oil is the temperature at which is breaks down, starts to smoke and taste bad. The low smoke point of olive oil is why it should not be used at high temperatures. Avocado oil therefore is a very suitable healthy oil for high temperature frying and baking.
Some researchers think that olive oil has some additional compounds in it, as well as the monounsaturated oils, that are responsible for its healthy properties. So perhaps it would not be a good idea to totally replace olive oil with avocado oil, but perhaps to consume both oils. That is what I intend to do.
The avocado oil that I bought was similar in price to a medium price olive oil, I think about $16 for 500 ml (approx a pint). Give it a try. If you can’t get it locally, it is available online.
photo credit: samantha celera
Technorati Tags: avocado oil, beta-sitosterol, smoke point, vitamin E, olive oil, monunsaturated fat
Less Sleep, Catch A Cold
January 13, 2009
Yesterdays post was Less sleep, higher risk of heart disease. On the same theme of getting enough sleep, there is the finding that getting less sleep makes you more likely to catch a cold and that the symptoms may be worse.
In this study, reported in the New York Times, participants had their sleep patterns analyzed and then were infected with a common cold virus, a rhinovirus. Colds can be caused by a number of viruses, with rhinoviruses being the most common.
To infect the study participants, a solution containing rhinovirus was dripped into the noses. There were 153 study participants, and 135 were found to be infected by the rhinovirus. The presence of a cold was assessed by both the presence of signs and symptoms of a cold, and by analysis of nasal lavage (washing out the nose).
Prior to the infection, for several weeks the study participants were interviewed once a day, by phone, on their sleep habits for the previous day. An overall sleep efficiency was assigned to each study participant.
When the sleep efficiency and infection levels were analyzed, it was found that those with poor sleep efficiency were more likely to have common cold symptoms. The participants who got less than 7 hours sleep were more than twice as likely to have cold symptoms as those who got at least eight hours sleep. Additionally, the level of infection was much lower in those that had high sleep efficiency.
So, this study suggests if you do not get much sleep each night that you are more likely to catch a common cold, and have worse cold symptoms than if you get plenty of sleep at night.
Yet another reason to make sure that you routinely get plenty of sleep.
photo credit: Jeramy & the Octoberlings
Technorati Tags: less sleep, common cold, rhinovirus, cold symptoms
Less Sleep, Higher Risk Of Heart Disease
January 12, 2009
Do you get enough sleep? Do you get your eight hours per night? A new study suggests that shortage of sleep can lead to a higher risk of heart disease.
The new study looked a study population that has been followed for many years. The participants were analyzed in 200-2001 and again in 2005-2006. In 2000-2001 the study participants’ ages ranged from 35 to 47 years old.
The researchers measured sleep metrics (this name made me laugh). Included in sleep metrics were sleep duration and fragmentation, daytime sleepiness, overall quality of sleep and self reported sleep. The duration and fragmentation of sleep were measured by a wrist actigraphy. A wrist actigraph is small unit that looks like a wrist watch, usually worn on the non-dominant wrist, which measures and records movement.
The other measurement was of coronary artery calcification. As plaque in the arteries develops calcium is deposited. This deposit of calcium is part of “hardening of arteries”. The amount of calcium in an artery can by measured by CT scan (computed (axial) tomography, CAT). The amount of calcification is an indicator of the amount of plaque. The presence of calcium indicates the presence of plaque, and more calcium means more mature plaque and an increasing risk of heart attack.
The participants chosen for the study had no detectable calcification at the first time point in 2000-2001. At the 2005-2006 time point those who had the longest sleep times were least likely to have any calcification. Those participants who got the least sleep were most likely to have calcification.
The levels of calcification ranged from 6% in those who got at least 7 hours of sleep, to 27% for those who got less than 5 hours sleep. This is quite a large difference in just 5 years. The length of sleep was the only parameter that was directly related to calcification. The other sleep metrics and factors such as blood pressure did not directly relate to the presence of calcification.
Another reason to make sure that you get a good amount of shut eye.
Technorati Tags: sleep, heart disease, calcification
How Overeating Can Make You Eat Even More
January 8, 2009
There was an interesting segment on NPR this morning. It talked about how overeating can make you eat even more. Made me reflect on the holiday season and my excesses.
Did you know that mice that are fed a high fat diet change their sleeping habits? They get up in the middle of the night and eat. This was interesting to me, since both of the two people that I know that have a serious weight problem will sometimes get up during the night and eat.
The suggestion in the segment is that perhaps if you eat a low fat diet you might sleep better. Presumably due to your body not wanting wake in the middle of the night. I would be interested to see whether it was generally a high fat diet that caused the waking during the night, or a high fat meal in the evening.
The segment also had several other interesting factoids. The first of which I knew, but not the two others.
If you eat a lot of food at one meal this causes a large increase in the amount of glucose in the blood. Your body will have to produce a lot of insulin to deal with it. Under conditions of large amounts of glucose in the blood, the production of insulin may overshoot, so that too much glucose is removed from the blood. These low levels of glucose result in a feeling of being tired, perhaps dizzy, and even feeling sick. The remedy for this is eating more food!
If the stomach keeps getting stretched, the signaling mechanism from the stomach to the brain, telling the brain it is full may malfunction, and so you don’t know you are full and keep on eating. This will lead to not being aware of eating too much, if you don’t carefully take notice of portion size.
If you have a very cold drink with your meal it makes the stomach contract. This contraction causes the food in the stomach to leave sooner that it would than if not prematurely contracting. This results in feeling hungrier sooner. This then leads to overeating by shortening the time between meals or snacks. So no more cold drinks for me, back to the British warm beer.
The body is amazing in its ability to regulate itself. However, as this information on overeating demonstrates, some of those mechanisms can, under certain circumstances, actually work against you and make the situation worse, and unfortunately much harder to deal with. Sometime life (and the body) does not seem fair.
The segment was entitled Gut reaction: Overeating can impair body function
photo credit: flem007_uk
Technorati Tags: overeating, stomach, insulin
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