The Diet Wars Really Are Over
John Tierney over at TierneyLab recently had a bit to say about the New England Journal of Medicine study that compared an American Heart Association low-fat diet with Atkins and Mediterranean diets.
I’ve discussed the details and the implications in a longer page post called Diet Wars, but the upshot of this and many other bits and pieces of nutrition research from recent times pretty much suggests that we stop wasting time debating low-fat or low-carb or in between and get on with recommending a healthy eating pattern that spans a wider macronutrient range for fat, protein and carbohydrate.
Let’s get the faddists, fanatics and false prophets on the run.
When Aerobic Fitness is Not Aerobic Conditioning
Photo: Ernst Moeksis
Aerobic fitness is measured by the volume of oxygen you can process in any given time. This is called your VO2 maximum or VO2max. It’s mostly measured in millilitres of oxygen used per kilogram of bodyweight per minute.
An elite marathon runner might have a VO2 of 80 and an obese, sedentary and very unfit person of the same age around 35.
You mainly get very high VO2 by doing aerobic or cardio training for lengthy sessions, usually in one block; say, an hour or running, cycling or similar activity. But . . . you can also get a reasonably high VO2 — but not as high as a marathon runner — by doing higher intensity exercise for less time. This might involve sprints or middle distance intervals at high intensity, or even workouts like this one in the gym without running at all. Training for team sports can provide this sort of aerobic fitness. Typical VO2 in elite athletes in sports like football (soccer) might be around 60 to 65, with some individuals even higher.
Why You Need Cardio for Health
‘Cardio’ like walking or slow jogging on treadmills is often recommended in heart rehabilitation programs or for the very unfit in order to build up heart and lung fitness. This is much less stressful than doing higher intensity intervals for a shorter time. And regular, moderate-intensity, sustained aerobic exercise conditions other aspects of your body other than your ability to to get fitter faster, which is perceived as one benefit of interval training.
Aerobic conditioning of the longer, slower type builds the small blood vessels called ‘capillaries’, in muscles, — the heart is a muscle — and these are encouraged to grow throughout muscle tissue to facilitate oxygen supply at times of high demand. With this sort of conditioning, your heart has extra blood supply and it gets bigger and stronger as well. For example, in one study, two groups were trained, one doing continuous, cardio type exercise, and the other shorter intervals of higher intensity. The longer, slower cardio group added twice as much capillary capacity as the interval trainers.
This might even be important if you were unfortunate enough to suffer a heart attack. The extra blood supply, called ‘collateral supply’ could save your life.
You will get some of this capillary conditioning with interval training, but the big benefits mostly come from regular, sustained aerobic type exercise — jogging, running, cycling swimming for 30 minutes or more at a session. Naturally, the higher-intensity interval type exercise will improve your anaerobic performance if you need this for sports.
If you’re training for health and fitness, don’t put all of your eggs in the weight training and high-intensity interval training baskets. Find time to fit in some good, old-fashioned cardio.
Effect of interval versus continuous training on cardiorespiratory and mitochondrial functions: relationship to aerobic performance improvements in sedentary subjects. Daussin FN, Zoll J, Dufour SP, et al. Am J Physiol Regul Integr Comp Physiol. 2008 Jul;295(1):R264-72. 2008
How the Cholesterol Skeptics Can Harm You
Pic courtesy jslander
Do a search for ‘cholesterol and heart disease’ in Google and you will see that many of the results in the first few pages are from sites that dispute the current medical view that cholesterol is a major factor in causing heart disease.
Some of the advocates of this position are well known ‘alternative’, or at least fringe movements that have a particular dietary barrow to push. Many belong to the low-carb brigade, indigenous diets advocacy, Paleo nutritionists, and sadly, some bodybuilders and weight trainers and men’s health advocates. And, of course, it should be said that many reputable people within these movements do not accept the ‘cholesterol myth’ line.
Cholesterol is a factor in heart disease and these people are dangerously wrong. They rely on dumbing down a complex scientific issue to impress a gullible audience. I could write a long review of this issue, fully supported by references, but I won’t waste my time, or yours. Here are a few crucial points to consider.
It’s the Cholesterol, Stupid!
- In the condition familial hypercholesterolemia (FH), individuals have naturally very high cholesterol levels as a result of a genetic abnormality. If undiagnosed, or without treatment, such people can die of heart attacks in childhood or in early adulthood depending on the severity of the condition. Brown and Goldstein won the Nobel Prize for their work on cholesterol, HF, and how cholesterol causes cardiovascular disease. The science of HF alone, should be enough to send the cholesterol skeptics packing — but still they persist.
- Although I am no promoter of pharmaceutical company interests per se, there is little doubt that statin medications improve heart disease conditions and fatal outcomes in people with high cholesterol by a combination of lowering LDL cholesterol and probably raising HDL cholesterol. The evidence is just too overwhelming. In fact, in recent years, the cholesterol skeptics have subtly shifted their attacks from “cholesterol does not cause heart disease” to, “saturated fat does not cause heart disease”, which is a softer target for them considering the complexities of different chain length saturated fats and the interactions of mixed diets.
- The skeptics like to juggle the medical literature to try to show that there is no valid evidence linking high cholesterol to heart disease. However, it’s not in dispute that heart disease is dramatically low in healthy populations with total cholesterol levels under 150 mg/dL or 3.9 mmol/L. Cardiovascular disease rises with increasing total cholesterol, and especially LDL cholesterol, in most populations.
- Even so, some populations in some countries seem to defy this trend, and these are the people the skeptics concentrate on when delivering their message. The thing to remember is that heart disease is multifactorial — that is, cholesterol may only be one factor among several, even though it is a major factor. Some populations will, through genetics or lifestyle, defy the atherogenic effects of higher cholesterol to some extent. This seems to be the case with the ‘French paradox’, in which French populations have much lower heart disease than other country groups with similar cholesterol levels. That does not mean that cholesterol is not a major factor in heart disease for most populations.
Overall, considering the established science of familial hypercholesterolemia, and the evidence from statin drug trials, including regression of plaque with cholesterol lowering, the evidence is so overwhelming for a dominant role of blood cholesterol in heart disease, and the influence of poor nutrition in raising blood cholesterol, that one can only assume the cholesterol skeptics have another agenda. I don’t know what it is, but it doesn’t take too much thought to come up with a list of industrial food interests that might benefit from this hogwash. Believe them at your peril.
Tim Russert’s Heart Attack - What Went Wrong?
According to a New York Times article, Tim Russert, the well-known NBC news and current affairs television journalist who suffered a fatal heart attack, did not have any prior warning even though he did have some ominous signs in his cardiovascular risk profile.
The essence of many articles about Tim Russert since his death have emphasized his compliance with doctors’ recommendation and prescription — exercise, lower cholesterol, lose weight, healthy diet and so on. How could someone, presumably doing the right things, still have a fatal heart attack?
The New York Times article points out that even allowing for these positive things, he was quite overweight and had low high-density cholesterol and high blood triglycerides. This constellation of measures is known to some practitioners as the “metabolic syndrome”, although not all recognize this term or if it is a syndrome at all. Either way, it means greater risk of a heart attack.
Waist Circumference and BMI
It’s risky business when you’re over 40 and have these markers of cardiovascular risk. And there are no guarantees that technology can reduce your risk to zero. Even people with very low risk markers still fall over dead with sudden heart attacks. It’s all about numbers, percentages and how you improve your chances.
Getting that waist to below 38 inches or 95 centimetres for men, and 32 inches or 80 centimetres for women, is a good place to start. Alternatively, a waist to hip ratio of 0.9 for men and 0.8 for women, or less, is also a good guide to healthy weight. Divide your hip measurement at the widest by your waist measurement at the narrowest, usually around the naval.
The body mass index (BMI) scale is less useful because it gets distorted for relevance by how much muscle you carry. Bodybuilders, weightlifters and athletes are often unfairly placed in the overweight categories, which are at BMI 26 or more. BMI can be measured by dividing your weight in kilograms by your height in metres squared.
Does Coffee Kill or Cure?
Coffee, Java, Joe, Mud, Beans, Cafe — whatever you call it — coffee is the most popular drink on the planet, in international terms. Even so, in “natural health” circles it was, and perhaps still is, regarded as just about as evil as alcohol. Natural health people don’t like substances that either stimulate or depress the nervous system like coffee and booze do respectively. A naive evaluation for sure.
But what if coffee turned out to be just about as health-giving a herb as you can get? Wouldn’t that be a surprise?
Here’s what recent research has discovered about coffee. Keep in mind that the coffee industry is enormously powerful and no doubt some scientific work is sponsored by the industry. However, enough reputable and independent scientists are involved in this research to suggest there is something to take note of.
Diabetes Prevention
Coffee consumption seems to lower the risk of type 2 diabetes significantly, and this association turns up in research as far afield as Europe, Japan and the USA in at least 12 different studies. Caffeinated and decaffeinated coffee seem to have similar effects and some component of the coffee bean other than caffeine is suggested as the protective compound. Chlorogenic acid is one such natural chemical compound, perhaps acting as an antioxidant.
Surprisingly, caffeine studied by itself seems to impair insulin sensitivity and glucose tolerance, so one might expect coffee to have the opposite effect. It doesn’t seem to be so. Most authorities suggest limiting coffee consumption to around 3 cups each day to be on the safe side.
Parkinson’s Disease and Liver Disease
Similarly, there is reasonable evidence that coffee drinking protects against liver disease like cirrhosis, and also the debilitating Parkinson’s disease, a disease that affects the brain’s production of dopamine, a chemical neurotransmitter required for coordinated movement. There is some consistency to this evidence as well.
What’s Wrong with Coffee?
Heart disease
You may be aware that in the past, coffee and caffeine were assumed to be bad for the heart: raised blood pressure, increased heart rate, cholesterol and so on. People with heart disease and those recovering from heart bypass surgery were urged to avoid coffee and even tea, with the stimulant caffeine being the most problematic agent. But now, cardiologists are not so sure. It seems that the coffee/caffeine and heart disease risk may have been overestimated and that some aspects of coffee drinking could even be beneficial.
Distinctions are made between the effects of boiled and filtered or instant coffee. Boiled coffee is traditionally a Scandinavian method of brewing with coffee grinds subjected to hot water with no filtering. Filtering with paper or metal filters is supposed to take out the potentially harmful chemicals cafestol and kahweol, which are reported to raise cholesterol. Some studies show that boiled coffee could be more hazardous than filtered coffee for heart disease, but I think this needs more follow-up to be certain. While for some people blood pressure seems to adjust to coffee consumption, others seem to have a genetic tendency for increased blood pressure with coffee consumption.
Overall, moderate consumption of filtered or instant coffee — up to 3 cups daily — seems to have little effect on heart disease risk.
Osteoporosis and Miscarriage in Coffee Drinkers
I’ve put both of these long-held beliefs, or at least suspicions, related to coffee together because they mainly affect women directly. The most recent research suggests that caffeine may increase your risk of miscarriage when you drink more than about one cup of coffee or 100 milligrams of caffeine a day. Some research also points to marginally lower birth weights in higher caffeine consumers.
Moderate consumption in the range of up to 3 cups of coffee daily probably has little effect on osteoporosis or bone fractures according to the most recent studies.
Summary
As the epidemiologists like to say, more work is needed to confirm these associations, but overall, moderation is the way to go — around 3 cups a day is unlikely to be harmful and may even be beneficial in some respects — with perhaps a reduction of consumption when pregnant. Coffee is a stimulant and some people do not deal with the caffeine hit as well as others. I can drink coffee before bed and it won’ t keep me awake. But that’s not for everyone. If you get heart palpitations or sleeplessness, drinking less coffee, cola drinks or strong tea is worth a try.
Heart Disease on the Increase for Women
While breast cancer is often a health focus for women, disease of the heart and arteries is the leading cause of death among men and women in most developed countries, accounting for about half of all deaths and associated illness.
In recent years, cardiovascular disease and deaths from it, in some groups of women, has been rising faster than for men.
An increase in type 2 diabetes, which is especially potent in women, may be the cause according to a new study in the American Journal of Lifestyle Medicine — and most of it is preventable with diet and exercise — a message that is already widespread.
Apparently, in the Nurses Health Study — a long-running evaluation of the health of nurses — 82% of coronary heart disease cases and 91% of diabetes cases in women could be prevented by avoiding smoking, eating a healthy diet, maintaining normal body weight and exercising regularly. Not much to ask, surely . . . and the story is much the same for men.
In fact, it is a lot to ask of many people. The message is understood, the implementation is much more difficult. Finding a way around this impasse can be a personal challenge and a public one.
Booze! Someone’s Got To Do It
You won’t find many doctors telling you to start drinking if you don’t already. They’re terrified of creating alcoholics. The truth is, drinking in moderation — and that’s the gotcha — seems to have substantial benefits, from heart disease to bone strength and, possibly, for preventing rheumatoid arthritis.
The Bad Stuff First
Moderate drinking is regarded as two drinks a day for men and one drink for women. It’s a fine line considering all the risks . . . because alcohol is a carcinogen of some power. Forget a few suspect food additives, alcohol is a known or highly suspect carcinogen (cancer causer) of the mouth and throat, breast, liver, pancreas, colon and perhaps stomach. In a statistical sense, the risk starts at one drink a day, but bear in mind that your diet and physical activity habits can lower your risk as an individual — or increase it as the case may be. Get the picture?
In addition, too much alcohol just destroys your liver — cancer or no cancer — and your brain.
The Good Stuff - Heart Disease
Moderate drinking seems to reduce the risk of heart and artery disease. Quite a few studies show that non-drinkers and heavy drinkers tend to have more heart disease than low or moderate drinkers. Red wine seems to have its own special place in the risk-reduction hierarchy, and most of this is attributed to the red antioxidant called resveratrol in red wine — but it could be something else.
The Good Stuff - Bone Density
Moderate alcohol consumption improves bone density. There, I’ve said it. This one is a bit of a sleeper because no one wants to tell women to drink alcohol because of the well-studied relationship with breast cancer. Even one drink a day tends to raise the risk of breast cancer. But again, eat well and exercise and you might just reduce this to even — and you get some bone protection as well. I’m just speculating but it’s not an unreasonable speculation.
The paradox is that alcohol (ethanol) can have estrogenic effects, which is probably how it increases breast cancer risk. At the same time this may be how it increases bone density, especially in postmenopausal women. Moderate drinking seems to provide some bone density protection for men as well. The finer points and the consumption patterns are not that well understood, so watch for revisions of this information. And needless to say, too much booze can make you fall over. Don’t overdo it. Most fractures occur from falls. Again, red wine might just be the best bet if you do partake of the demon drink.
The Good Stuff - Rheumatoid Arthritis
This one is much more contentious because the evidence is not as good. Rheumatoid arthritis is an auto-immune disease that attacks the joints. Recent studies have provided some evidence that non-drinkers have more incidence of this disease — up to 50% more. It’s worth noting, although perhaps people with rheumatoid arthritis are inclined not to drink as much.
Summing Up
Boozing has risks, especially if you define boozing as more than one or two drinks a day. And for cancer, even this may be risky for some people, especially those with a family genetic component and poor lifestyle approach.
If you eat lots of whole plant foods and exercise most days of the week you can lower your risk of cancer and heart disease (and diabetes). Moderate drinking has benefits that are worth knowing about as well. How you use that information is up to you.
Vitamin D Deficiency May Cause Heart Attacks
As reported by Reuters health, a new study by Harvard University health researchers has found that men with the lowest blood levels of vitamin D are more susceptible to heart attacks, especially fatal heart attacks.
Vitamin D improves calcium absorption and is important for bone health and to prevent osteoporosis. In addition, adequate vitamin D seems to offer protection against other diseases such as cancers of the colon, breast and perhaps pancreas. The lower level of normal is 30 nanograms per millilitre of blood. The men with the greatest risk in this study had levels as low as 15 nanograms.
What you need to know
Vitamin D is formed in the skin from sunlight exposure — and is available in fortified milk and margarine products and fatty fish like salmon and sardines. Sunscreen will block vitamin D absorption so it’s important to ensure a balance between sunlight exposure and the skin cancer risk of overexposure and sunburn. Supplements are an option, but you need to get medical advice because too much can be toxic.
Personally, I try to get as much gentle sun exposure in the early hours in summer or in winter when sunburn risk is least. I do this at the beach or by training outdoors. Tanning booths are not recommended and can be dangerous.
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