Probiotics: Caveat Emptor
You may well have heard the advice that we all need to keep the bacetria in our intestines healthy. Countless experts have recommended that, as long as we are not lactorse intolerant, we should regularly take some live yoghurt to "re-colonize" our intestines with nice friendly bacteria.
There has just been a briefing in London to warn the public that as many as half of the "probiotic" or "friendly bacteria" products on sale in the United Kingdom could be ineffective and some may even be harmful.
The experts on the panel included Professor Glen Gibson from the University of Reading who is an expert in food microbiology, and recommended sticking to products made by major manufacturers. Too many of the other productsmight not contain the numbers of bacteria advertised, and the icrobes might not survive long enough in the intestines to do much good.
The evidence that probiotics help is still far from settled, as discussed in a recent review. But there are enough reports to think that probiotics may be helpful for irritable bowel syndrome and perhaps inflammatory bowel disease.
An even newer area or interest in the use of "prebiotics:" short-chain carbohydrates that alter the composition, or metabolism, of the intestinal organisms in a beneficial way.
Make sure that if you are using a product, it comes from a reputable manufacturer, and that it contains at least 10 million bacteria. And as I said in my title, "Caveat Emptor," "Let the buyer beware."
BMI R.I.P.
For experts in metabolism, we have long worried about the over-emphasis on the use of body mass index (BMI) as the arbiter of a "healthy" weight. It is one of those measurements that is in some senses too easy, and the results are deceiving. I regularly see people claim that a certain BMI will "predict" the risk that someone will develop cardiovascular disease or diabetes. The truth is very diferent.
There are two ways to calculate your BMI:
1. Metric system – Kilograms and Metres
[Your weight] divided by [Your height squared]
2. Imperial System – Pounds and Inches
[You weight] divided by [Your height squared] times 703.5
A person is said to be healthy if his or her BMI is between 18.5 and 24.9.
The trouble with this is that the calculation lumps together fat and muscle: a muscular six foot tall football player weighing 300 pounds and with 3% body fat, would have an "unhealthy" BMI of 26.3. That is clearly absurd, and one of the reasons that most experts use BMI only as one part of an evaluation of health.
Our scepticism has been confirmed by an important study from the Mayo Clinic in Rochester, Minnesota, and published in this week’s issue of the medical journal The Lancet.
The researchers looked at 40 studies involving 250,152 patients. Their analysis revealed that people with a BMI of 30-35 were at lower risk of cardiovascular disease than those whose BMI was below 20.
BMI does not correlate well with fat. A better way to distinguish between fat and muscle is to take a cross-sectional view of the abdomen, and to focus on the waist-hip ratio.
A separate study by researchers at the London School of Hygiene and Tropical Medicine of 14,833 people over the age of 75 was published in the American Journal of Clinical Nutrition. They also came to the conclusion that BMI is a poor indicator of health in both men and women in this age group. These researchers also agreed that waste-hip ratio was a better indicator of mortality risk.
This is all music to my ears. For almost three decades we have been teaching about the importance of different stores of fat and the limitations of the BMI calculation. It has been known since the 1940s that gaining weight on the hips, or developing "lover’s handles" are only very weak predictors of diabetes and vascular disease: it is the intra-abdominal fat that is the problem.
There are particular problems with using BMI in the elderly and in some ethnic groups, especially people from the Indian sub-continent and Japan.
The bottom line?
BMI is misleading, and in some age groups and races, grossly misleading.
Much better to use weight and waist-hip ratio.
And BMI only if there is a space on the medical forms where they still need to have it filled in.
How Does Fiber Help You?
Unless you’ve been living on Mars (!), you will doubtless have heard of the advantages of increasing the amount of fiber in your diet. A high-fiber diet reduces your risk of colon cancer, constipation, hemorrhoids hypercholesterolemia and insulin resistance syndrome.
We have always wanted to know how fiber does so many magical things at once, and now we may an answer. In a paper published in the open-access Public Library of Science Biology today, by a group from one our local institutions – the Medical College of Georgia in Augusta – collaborating with a researcher from Josai University, Sakado, Saitama in Japan.
The epithelial cells lining the intestine have a life span measured in 1-5 days. They spend their short life times working to process enormous amounts of food residue on its way past. It is this layer of cells that acts as the barrier between the body and items floating past on the inside of the intestine.
Long before it became the topic of some popular books are over-enthusiastic magazine articles, we became very interested in the idea of the “Leaky gut:” the concept that some illnesses are a result of breakdown of the normal integrity of this protective barrier. Over 20 years ago, a friend and colleague at Northwick Park Hospital – Ingvar Bjarnason – did some pioneering work on this important issue. Several recent studies have indicated that a breakdown of this barrier may be involved in several childhood illnesses including allergies and asthma. There is also some early information suggesting that “leaky gut” may be involved in some autoimmune processes involving the intestine. Both zinc supplementation and oats may prevent gut leakiness under certain very specific circumstances.
When the epithelial cells in the gut wall encounter indigestible fibrous foods, the outer covering of the cell ruptures, releasing a coating of cell-protecting mucus. In a matter of seconds, the cell begins to repair itself, in the process releasing yet more of the beneficial mucus. Not only does it lubricate, but also it may keep some carcinogens and allergens out of your system.
The constant buffeting of the cells causes mild damage that increases the level of lubricating mucus. Injury at the cellular level promotes the health of the gastrointestinal tract as a whole.
Here we see a basic principle of nature: many of the same things that apply in the cells of the body apply equally in the life of someone trying to achieve success. Without the buffeting, the cells of the intestine could not produce the mucus on which your life depends.
Without some occasional adversity, you will find it more difficult to grow as a human being.
“Storms make oaks take deeper root.”
— George Herbert (English Religious Poet, 1593-1633)
“He who knows no hardships will know no hardihood. He who faces no calamity will need no courage. Mysterious though it is, the characteristics in human nature which we love best grow in a soil with a strong mixture of troubles.”
–Harry Emerson Fosdick (American Clergyman, Writer and Broadcaster, 1878-1969)
Blueberries
One of the principles of integrated medicine is that anything that’s good for you should have more than one benefit. So omega-3 fatty acids may help with cardiovascular health, mood, memory, attention deficit disorder, as well as the health of skin and bones.
Another one is the blueberry. I’ve been sufficiently impressed by the data on the health benefits of blueberries to have been a regular grower and consumer for years. They contain a number of potentially healthful compounds including polyphenols and anthocyanins, which can help modulate and balance the free radical systems of the body. Remember what I said recently about the value of keeping some free radicals in the body? The last thing that we want to do is to be rid of all of them!
There is reasonably good evidence that regularly eating blueberries can support cardiovascular health and there have been suggestions that they may reduce the risk and aggression of cancers of the prostate and colon.
There is also some evidence in animals that some of the components of blueberries may reduce inflammation and the effects of strokes – interruptions to the blood flow in the brain.
As a consumer, I’ve been carefully watching the growing evidence indicating that blueberries – or some of their constituents may have effects on animal cognition, brain aging and the normal neuroprotective mechanisms in the hippocampal region of the brain.
We do not yet have proof that these same effects occur in humans, and there are always three questions when we look at nutritional data:
- Can we extrapolate from the animal to humans? Mice are not men
- Are the amounts of blueberries or blueberry extracts even close to what humans could consume without spending all day eating, or getting a terribly upset intestine? There have been countless reports of the benefits of supplements that had to be taken in the most enormous doses to do any good. I’ve mentioned before the problem of L-arginine, which is sold as a “Natural Viagra.” Except that you need to take around nine grams for it to do much good, and most supplements contain less than a tenth of that. Regular readers will also remember my report concerning an article on coffee and sex. It was said that coffee would raise a woman’s libido. And indeed it does, if she drinks at least ten large cups of coffee at once. And coffee is a marvelous diuretic.
- When extracts are used, are we sure that we are getting the correct ingredient of the fruit? Many beneficial fruits contain just the right combination of nutrients to help us, so each can be taken in a small dosage or concentration. As with so much in integrated medicine, combinations are key. Take out one extract of a fruit, and you may lose the clinical effect that you wanted.
All that being said, the evidence is becoming progressively more interesting, and there is enough suggestive evidence for me to keep packing away the blueberries.
And just to show that I leave no stone unturned when checking the literature on your behalf, I rejoiced to learn that supplementing the diet of Arctic char with various supplements – including blueberries – improved the quality of his, ahem, semen. I do not know how this information will help any of us yet. Neither do I really know why a fish would want to eat blueberries or any of the other supplements that they were tried on. Though I’m sure that people have often asked similar off the wall questions about some of my research….
Free Radicals, Aging and Small Hairless Creatures
I’m accused of many things.
Apart from the oft-repeated falsehood that I was the inspiration for Hugh Laurie’s brilliant characterization of the cranky Dr. Gregory House (I definitely was not!), I have been accused of having a fixation with mole rats. Well, that one is partly true: they are fascinating little creatures.
But let me start at the beginning. Over the last three decades, free radicals have entered the national vocabulary. In the 1983 James Bond movie, Never Say Never Again Edward Fox orders Sean Connery to enroll in a health clinic in order to "eliminate all those free radicals."
Free radicals are found in nature: they can be derived from combustion and some other chemical reactions and they are generated in the atmosphere by the action of ultraviolet radiation with chlorofluorocarbons. But most found in the human body don’t come from the environment: they are generated by biological processes. The majority are extremely short lived, but a few special types can hang around for hours.
An excess of free radicals has been linked to an array of illnesses, including:
Some cancers
Diabetic vascular disease
Parkinson’s disease
Schizophrenia
Alzheimer’s disease
Emphysema
Age-related changes in the skin
Macular degeneration
This list just names a few: many other illnesses have been laid at the door of free radicals. You will often see people talking about “oxidative stress,” to describe the damage done by an excess of free radicals. There is a theory that normal aging may be a result of the gradual increase in the production of free radicals in the body
There is something to all this: I did some research on the role of free radicals in diabetic vascular disease in the 1980s, and made some interesting discoveries. It has recently been shown that an excess of free radicals in the wrong place can play a part in generating insulin resistance.
The trouble – as with so many apparently simple ideas – is that many of the popular concepts about free radicals are over-stated or even wrong.
We first have to ask ourselves, “If free radicals are so bad, then why does the body produce them at all?”
The answer is that free radicals play a crucial role in a number of important biological processes, including the killing of bacteria by a group of white cells known as granulocytes. They are also thought to be key cancer killers and prime mediators of normal communication between cells.
Yet they have been pilloried: thought to be the key to so many illnesses when, in fact, they are intimately involved in normal biological processes: if you had no free radicals you would probably die quickly and unpleasantly. We know that because there is a group of rare, fatal illnesses in which children cannot generate free radicals.
Rather than focusing on ways to eliminate free radicals, we should be dealing with ways to balance them.
Our bodies are loaded with sets of enzymes whose task is to mop up excessive numbers of free radicals. The most important of these are superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase.
When you see an advert or article extolling the virtues of some product because it abolishes free radicals or “reactive oxygen,” you know that you are dealing with some nonsensical marketing. Not science.
Fortunately, despite the marketing hype, it’s virtually impossible to obliterate all the free radicals in your body: Some must remain in your system or you will run into all kinds of medical problems.
Let me give you two examples of research that has shown first the good side of a producer of free radicals and second, one of the reasons why we know that there is more to aging than free radicals.
A study from France looked at a dye called mangafodipir that is used in MRI scanning. It was found to increase the cancer-killing ability of some chemotherapy drugs, while at the same time protecting normal cells. Mangafodipir was found to help promote the production of hydrogen peroxide while at the same time, through different biological mechanisms, protecting healthy cells from damage.
The second piece of research concerns my mole rats. I’ve talked about them before. They are extremely long lived: most reach the age of 25-30. And they seem never to get cancer. There are very few species that are spared from cancer: sharks rarely get the disease and there are some simpler organisms that also seem to be spared. So these mole rats have attracted the attention of researchers. What is more, they have very high levels of DNA damaged by oxidation so by rights they should get cancer and age prematurely. The fact that they don’t is leading to a whole new line of thinking about aging and illness.
So the message should be this: oxidative stress may be a factor in illness and aging, but your aim should be to modulate the free radical systems in your body, not to obliterate a key cancer killer.
Eat a diet that is rich in antioxidants
Don’t try and avoid stress: you can’t. Learn to manage it
Take regular physical exercise
Avoid environmental toxins such as smoke, excess sunlight, pesticides and radiation
Insulin Resistance, Diabetes and the Timing of Meals
At a meeting of the American Diabetes Association in June 2006, Professor Markus Stoffel from the Eidgenossische Technishe Hochschule in Zurich and Rockefeller University in New York, received the Outstanding Scientific Achievement Award for his extremely interesting and important research on the molecular mechanisms involved in the developmental insulin resistance.
This may sound as interesting as watching paint dry, but in actual fact the research is supremely practical, and may lead to a complete re-working of some commonly used dietary strategies.
Many physicians have not yet been taught that the liver is the key organ involved in the genesis of insulin resistance and of type 2 diabetes mellitus. Up to 90% of the glucose circulating in your blood has come from your liver. As the liver becomes less sensitive to the actions of insulin, it starts producing more glucose, particularly after meals. This in turn causes blood glucose to rise and with it insulin levels. One of the other consequences of insulin resistance is that the liver stops storing triglycerides, which then start circulating, while at the same time storing other types of fat, leading to what we call, not surprisingly, fatty liver. Or in the dog Latin that doctors use to confuse the general public, hepatic steatosis.
When we are fasting, the liver switches on banks of genes that produce the enzymes responsible for oxidizing fatty acids to produce fuel.
The main objective of a balanced diet is to maintain balance: we want to avoid sudden swings in glucose, fatty acids or insulin: it is these sudden changes that can cause inflammatory changes in blood vessels and in the liver and may lead to some of the circulatory problems that are such distressing complications of diabetes. We want to try and keep our insulin levels smooth and low. The best way not to do that is to have frequent high calorie snacks and to eat late at night. The best way is to follow the plans that I’ve talked about before. Eat little and often, keep the balance of nutrients just right, and be aware of the exact times at which you eat. Nothing except a little protein in the 2-3 hours before you retire for the night, and go very easy on alcohol, which can wreck your metabolism.
“The secret of life is balance, and the absence of balance is life’s destruction.”
–Hazrat Inayat Khan (Founder of the Sufi Order of the West, 1882-1927)
Technorati tags: Insulin resistance Diabetes mellitus Fasting Weight management
Cannabinoid Receptors and Cardiovascular Risk Factors
Clinicians throughout the world are looking forward to being able to use a new medicine for obesity called rimonabant, which will be marketed as Acomplia by Sanofi-Aventis. It was launched in the United Kingdom yesterday, after being given official European Union marketing approval last week. We do not expect to get it in the United States until sometime in 2007, assuming that the FDA gives it approval. The medicine is not cheap, but interestingly there is also some data to suggest that it may help some people stop smoking.
So why the interest? The original idea for the compound was based on the observation that many people become very hungry if they use cannabis and specific cannabinoid receptors were found in the brain that are responsible for many of the actions of the drug.
A recent and important study involving a two-year investigation of 3045 obese or overweight individuals was published in the Journal of the American Medical Association. It indicated that treatment with 20 mg/day of rimonabant plus diet for 2 years promoted modest but sustained reductions in weight and waist circumference and favorable changes in metabolic and cardiac risk factors.
Only about half of the people in the study completed it, so we must interpret the data cautiously. The idea of using a pill to manage weight is appealing as a weight-loss aid for some patients. But as I have pointed out before, the control of weight is highly complex, and it is highly unlikely that a pill will be successful on its own. What are needed are long-term, comprehensive lifestyle changes, together with careful attention to the psychological and subtle aspects of weight control.
We have had a great many requests to publish our own comprehensive weight management strategy – The Atlanta Approach – that we have been using with great success for almost two decades. If there is interest in me doing so, I shall put our notes together into a downloadable eBook.
Technorati tags: Rimonabant Acomplia Cannabinoid receptor Weight management The Atlanta Approach
Add Years to Your Life and Life to Your Years: The Power of Small Changes.
I want to tell you about a mind bogglingly important study that many professionals have known about, but somehow hasn’t popped up on most people’s radar. The story was broken by the BBC last month. It is about an exceptionally important study that has been running in Norfolk, in Eastern England, as well as other parts of Europe since 1992. The British section is directed by Professor Kay-Tee Khaw who is Professor of Clinical Gerontology at the Department of Public Health and Primary Care at the University of Cambridge. The main focus of the Clinical Gerontology Unit is the maintenance of health in aging populations, with a particular emphasis on the combined role of lifestyle, environmental and genetic factors in chronic diseases.
The UK arm of the study has been following 25,663 men and women aged between 45 and 79 years old, looking at their diet, environment, lifestyle and health. The latest results from the study have confirmed several things that we already suspected: 1. Eating five portions of fruit and vegetables a day can give you the life expectancy of someone three years younger.
2. Not smoking turns back the clock by four to five years.
3. Even increasing exercise by a moderate amount can increase your life expectancy by three years. But the amount of exercise someone would need to do to achieve that depends on their job. A sedentary office worker would need to do one hour of exercise, such as swimming or jogging every day. By contrast, a person with a moderately active job, such as a hairdresser, would need to take 30 minutes of exercise a day. Here’s some more good news: People with very active jobs, including nurses and bricklayers, do not need to do any extra exercise – as their work is strenuous enough.
I think that just about anyone can take those baby steps toward a longer and healthier life
There’s an old Yugoslavian Proverb:
“Grain by grain a loaf, stone by stone, a castle.”
That seems about right!
Technorati tags: Health Longevity Preventative medicine Wellness
Sleep, Weight, Insulin Resistance and Diabetes
I am often asked why there seem to be such close links between food and mood. Not just comfort eating, or the sudden shock of lots of carbs when we need an energy jolt, but why drugs that alter mood so often alter appetite?
You will probably not know this, gentle reader, but I only learned of it from reading scholarly papers. Apparently many people report that using marijuana makes them very hungry. On the other hand, cocaine and amphetamine affect not just the metabolism, but also appetite. The link has to do with the evolutionary development of feeding behaviors with the motivation to find food and to be satisfied by it.
Another link that has interested me for many years is the connection between metabolism and sleep. We have always presumed that this link has to do with hibernation: even humans have maintained some hibernation responses.
There is extremely good evidence that there is an inverse relationship between the number of hours that you sleep and an increase in your weight. There have been a great many studies on this, but one of the best was published by a group of researchers from the Mood and Anxiety Disorders Program, at the National Institute of Mental Health, the Psychiatric University Hospital, Zurich, Switzerland; University of Pittsburgh School of Medicine and the Department of Psychosocial Medicine, Zürich University Hospital, Switzerland in the Journal Sleep in 2004.
A report from the BBC concerning a study presented to the American Thoracic Society International Conference in San Diego provides yet more evidence of this link between sleep and weight. Researchers from Case Western Reserve University in Ohio, followed nearly 70,000 women for 16 years. They found that women who slept five or fewer hours a night were a third more likely to put on at least 33lbs (15kg) than sound sleepers during that time. It also found that compared with women who slept for seven hours a night. lighter sleepers were 15% more likely to become obese (have a Body Mass Index (BMI) of 30 or more. {BMI is calculated by dividing your weight in kilograms by the square of your height in meters}).
Previous studies, some of which I have reported before, have shown that after just a few days of sleep restriction, the hormones that control appetite cause people to become hungrier. However the women in the study appeared to eat less. I say “appeared to,” since the use of personal evaluations of food intake are notoriously inaccurate.
In dozens of countries arond the world, I am regarded as an authority in the fields of endocrinology, metabolism and nutrition. But when a group of us tried to estimate our daily intake and compare it with meticulous diaries, we discovered that we – a group of internationally renowned experts – were off by around 500 calories per day.
All kinds of explanations have been advanced, from people who didn’t sleep getting up and binge eating; to the effects of sleep-deprived people craving high carbohydrate, high fat food; to insomnia being a result of anxiety or depression that releases hormones that cause us to lay down fat in our tummies.
For all kinds of complex biochemical reasons, I have always felt that a lack of sleep would lead to an increase in insulin resistance, that may cause an increase in the deposition of fat in key regions of the body.
Some new research suggests that I may have been right on this one. A group based at Yale University School of Medicine, in New Haven, Connecticut has just published a report that should be of interest to all of us, and in particular you multi-tasking insomniacs out there.
The investigators studied a cohort of men from the Massachusetts Male Aging Study who did not have diabetes at baseline (1987–1989) and who were followed until 2004 to look for the development of diabetes mellitus. They came to the conclusion that BOTH very short and extra long sleep durations increase the risk of developing diabetes, independent of confounding factors.
The take home message?
If you do not get 7-8 hours sleep each night, you are vulnerable to a great many problems, and perhaps the biggest of all is the risk of weight gain, insulin resistance and diabetes mellitus.
I do not recommend using sleeping tablets unless absolutely necessary, and then for just a few days at a time. Instead follow all the sleep strategies that I have talked about in earlier blog entries.
During a recent visit to Danville, Virginia, I was delighted to learn that one of the non-pharmacological approaches that I have found helpful – putting a cold compress on the abdomen – was used by General Stonewall Jackson who used this very technique that I had to learn by going all the way to China.
The bottom line? Before your sleep gets disrupted by being overweight and you develop sleep apnea, try some simple sleep hygiene, and a few of these novel techniques.
Technorati tags: Insulin Insulin resistance Insulin resistance syndrome insomnia alternative medicine resilience
