Year: 2002

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Peanut Allergies

Did you know that the majority of fatal and near-fatal allergic reactions in North America are caused by peanut allergy?

The subject of peanut allergy is very important to parents, school administrators and anybody who looks after children. It is time to revisit the subject.

Food allergy affects about six to eight percent of children younger than four years of age. It can affect older children as well.

Peanuts have been with us since they were first cultivated in South America about 2000 to 3000 B.C. But allergy to peanut appears to be a phenomenon of the past two decades.

April 25th issue of the New England Journal of Medicine deals with this subject quite nicely. The author of the article is Dr. Hugh Sampson, Paediatrician from Mount Sinai School of Medicine, New York. Here are some important points from the article:

-In spite of increasing public awareness of food allergy, most patients are not well prepared to deal with severe allergic reactions. Over 80 percent of patients who died from allergic reactions to food were not given appropriate information to avoid accidental food-induced reactions or use self-injectable epinephrine.

-Food-induced severe allergic reaction is often mistaken for severe attack of asthma or an acute cardiac event. Therefore, taking careful history of exposure to an allergen is important. There is no laboratory test to diagnose allergic reaction to food.

-Initial symptoms of peanut or food allergy are: tingling in the mouth and lips, sensation of tightening of the wind pipe, colicky abdominal pain, and nausea and vomiting, flushing of the skin, etc.

-Delay in the initiation of therapy such as injectable epinephrine is associated with a poorer prognosis, although about 10 percent of patients who receive epinephrine early still die.

-Up to one third of patients have a biphasic reaction – that is, these patients seem to have fully recovered when severe spasm of the airway suddenly recurs, requiring patient to go on a breathing machine. This usually occurs within the first four hours of initial treatment and recovery. So all patients should be observed in the hospital at least for four hours after they have successfully responded to initial treatment.

-In 25 to 35 percent of patients with peanut allergy, an allergic reaction to tree nuts (such as walnuts, cashews, and pistachios) will develop even though tree nuts are from a different botanical family.

-In vast majority of the patients the first reaction to peanuts occurs at a median age of 14 months. Many food allergies in children disappear as they grow. But peanut allergy often is a lifelong disorder.

In the next column, we will discuss what parents should do to teach their children about peanut and other food allergies. We will also tell you where to find more information on this subject.

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Fish and Omega-3 Fatty Acids

Fish on Monday, fish on Tuesday, fish on Wednesday, fish on Thursday, fish on Friday, fish on Saturday, a…n…d fish on Sunday!

What would happen to me if I eat all that fish?

There are several possibilities! I may turn into a fish. I may smell like a fish. I may incite my wife to throw me out of our smelly fishy house. My neighbours may name my residence as “House of Fish”. Or I may reduce my risk of getting a sudden heart attack!

What’s the right answer? Let us find out.

Within a month, two articles appeared on the advantages of consuming more fish each week (not necessarily everyday!). The first one appeared in the Canadian Medical Association Journal (CMAJ) titled – Omega-3 fatty acids in cardiovascular care. The second one in the New England Journal of Medicine (NEJM) titled – Food to Calm the Heart.

Fish and fish oils have omega-3 fatty acids. Also known as n-3 fatty acids. Whole grains, beans, seaweed, and soybean products also contain omega-3 fatty acids.

Eskimos have extremely low rates of death from heart disease because they eat lot of fish. Mediterranean diet is also high in omega-3 fatty acids.

A typical North American diet includes about one fish serving every 10 days. That is about 130 mg/day of omega-3 fatty acids. That is not enough.

Consumption of more fish does not stop one having heart disease. But it does help reduce the incidence of sudden heart attack. Studies have shown that if fish is fed to people who have had a heart attack, then fish can reduce the risk of sudden death by 45 percent.

But what about those who have had no previous heart problems?

The answer to this question is found in a study published in the recent NEJM. The authors studied 22,071 male physicians who were 40 to 84 years old in 1982 and had no history of a heart attack, stroke, or cancer. Their dietary intake of fish was studied, with measurements of blood n-3 fatty acids, and documentation of any cardiac problems during the 17 years of follow-up.

They found that the n-3 fatty acids found in fish are strongly associated with a reduced risk of sudden death among men who had no evidence of prior heart disease.

This information is important, as it is known that 50 percent of all sudden deaths from cardiac causes occur in people with no history of heart disease. Death is usually from irregular heart rhythm or coronary heart disease. Preventive measures (by way of increased consumption of fish) would help.

There is some evidence to suggest that consumption of fish may contribute to lower colon and rectal cancer, and breast cancer.

Next question is: how much fish should we eat and how often?

American Heart Association recommends at least two servings of fish per week, especially fatty fish (salmon, bluefish, mackerel, arctic, char, and swordfish).

The CMAJ article recommends three servings of fish per week. Eat fish that is broiled or baked. Avoid breaded fish products, fish sticks, fish and chips, and heavily salted or pickled fish. These are heavily loaded with unhealthy fat.

You can take fish oil capsules with meals. Or liquid egg enriched in mega-3 fatty acids. Vegetarians can find benefit from vegetable oils, nuts and seeds. We should strive for an intake of one gram per day of n-3 fatty acids.

Remember, heart disease is the number one killer in the industrialized world. If eating fish is going to save our population and civilization then let us eat fish on Monday, fish on Wednesday, fish on Friday, golf on Saturday, and go fishing on Sunday!

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PSA and Prostate Cancer

Does PSA screening reduce death due to prostate cancer?

PSA-based screening for prostate cancer remains a controversial issue, says an article in the Canadian Medical Association Journal (CMAJ).

Some health authorities in the United States advocate prostate cancer screening in men who ask about the PSA test. On the other hand, the Canadian Urological Association and most health authorities in the European Union still discourage the practice of prostate cancer screening, says Dr. Andre N. Vis, author of the CMAJ article.

In the United States, there was a gradual increase in the death rate from prostate cancer over several decades. But since 1993, the death rate from prostate cancer has gradually declined by 17.6 percent. Same thing has happened in Canada. Between 1991 and 1996, the death rate has declined by 10 percent.

Here is another example. Quebec experienced a 47 percent increase in the incidence rate of prostate cancer between 1989 and 1993. Probably due to introduction of PSA test. And the rate of prostate cancer death rate in Quebec decreased by 15 percent between 1995 and 1999.

The question is – is this decline in the death rate due to the effectiveness of screening with the PSA test? The PSA test was introduced in North American medical practice by the end of 1980s.

Some experts believe that the decline in the death rate from prostate cancer is due to better treatment options, change in diet and lifestyle, and may be improvement in environmental conditions. Not due to PSA screening.

Linda Perron and associates who did the research on the effectiveness of PSA screening in Quebec, says that, “In accordance with the observational studies described here, our results do not support the hypothesis that the present decline in prostate cancer mortality is attributable PSA screening.”

Perhaps the jury is still out on the effectiveness of screening for prostate cancer by PSA test. That does not mean that we should ignore our prostate. Thirty percent of men over 50 will have prostate cancer, but only 10 percent of these men will be diagnosed and treated for prostate cancer and three percent will die of the disease.
That means we have to be vigilant. We have to use whatever methods we have to detect prostate cancer early and treat it. And the methods of early detection available to us are two: digital rectal examination (DRE), and PSA blood test.

If you don’t have any symptoms of prostatic cancer does not mean you don’t have prostate cancer. That is why there is a big drive to screen asymptomatic men over 50 with DRE and PSA blood test.

Although DRE has a cancer detection rate of only 0.8 to 7.2 percent, it remains an important test that can be done easily in a doctor’s office. It also checks for anal and rectal tumours.

PSA blood test has a false positive rate of 20 to 50 percent and false negative rate of 25 to 45 percent. That means 30 to 50 percent of the time the test is wrong! So why do these tests if the returns are this low? The reason is simple – this is the best shot we have to get an early diagnosis!

If you are 50 years or older, and if you want to have your prostate checked out – in fact you should get it checked out – then talk to your doctor about digital rectal examination (remember, if you don’t let your doctor put a finger in your rectum to check your prostate then he might end up putting his foot into it!) and PSA blood test.

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How To Loose Weight

How much should Canadians eat?

That’s the question I ask of myself when I look at my girth in the mirror. Or stare at my bathroom scale six feet away from my eyes.

The other day, I took my last dress pants to a seamstress to make room for my ever-increasing girth. She says, “Dr. B, do some exercise!”

I thought I did enough exercise each week. May be I am eating too much! I did not think so. I thought I did both – ate less and did regular exercise. So what am I doing wrong? Why am I not losing weight?

I am not the only one asking this question. Million of Canadians and others in the world are asking the same question. What are we doing wrong?

Dr. C. Laird Birmingham, Professor of Medicine, University of British Columbia and Dr. Peter J. Jones, Professor of Dietetics and Nutrition, McGill University, have published an article in the recent Canadian Medical Association Journal (CMAJ) titled: How much should Canadians eat?

The professors believe that the current methods for assessing energy intake are flawed. These methods underestimate actual energy intake. Does that mean we are eating more than we think? The article also reviews new methods for measuring the energy content of foods and address the problem of energy expenditure in obese people.

Obesity is defined as an excessive accumulation of body fat. The body mass index (BMI) of over 30 is considered to be obese. BMI is measured by dividing the weight in kilograms by the square of the height in meters. Currently, about 20 to 30 percent of North American adults have BMI of 30 or more. These people roughly have 50 to 100 percent higher mortality rate than those with BMI of below about 25.

How do people become obese? When the amount of energy absorbed exceeds expenditure – the net gain of energy ends up as body fat. The authors say that the current wave of obesity epidemic are due to shifting perceptions about what constitutes a “normal” portion size, the increased availability to pre-prepared foods and the more sedentary “couch potato” lifestyles of individuals within developed societies.

The Canada Food Guide provides guidelines for food intake in Canada. Nutritionists follow these guidelines to advice individuals who want to lose weight. “Unfortunately,” says the CMAJ article, “the existing values contained in these guidelines are out of date.” They provide estimates of energy requirement that are erroneously low.

There are also biases in the methods used to measure expenditure of energy. Until these methods (for energy intake and expenditure) have been revised and updated, the energy intake should be individualized based on observation of outcomes based on BMI, blood lipids, and waist measurement, says the CMAJ article.

The most reliable indicator of energy balance or imbalance is individual’s weight. If a person is not losing weight then he is eating more than what he needs and he is not exercising enough – income is more than expenditure!

Whatever methods we use for measuring energy intake and output, one problem will always be there – obese people always underestimate their energy intake.

So, how much should Canadians eat? Is there an ultimate diet plan? Yes, listen to your weighing scale and measure your waist, if it ain’t going down then you are eating too much! And the best exercise you and I can do is to push ourselves away from the table. That is called will power! Your girth and weighing scale will tell you how much you should eat.

Start reading the preview of my book A Doctor's Journey for free on Amazon. Available on Kindle for $2.99!