A fishy story about mercury

I asked my friend if he heard about the Japanese man who had eaten sushi twice a day for two decades before dying of mercury poisoning. His priceless response: "At least he got to enjoy sushi twice a day for two decades." This short exchange illustrates very well the trade-offs we face every day as we aspire to preserve our good health.
Joking aside, should we be concerned with mercury and its baneful effect on our health? What is mercury anyway?

There are three chemical forms of mercury: elemental, inorganic, and organic, notably, methyl mercury. Exposure of the general population is primarily to methyl mercury and occurs through the consumption of fish and seafood. To a much lesser extent, the general population is exposed to inorganic mercury through dental amalgams.
Studies have shown that inorganic mercury comprises less than a quarter of total blood mercury. Thus, a measurement of total blood mercury consists primarily of methyl mercury.

Chronic exposure to methyl mercury may cause numbness and tingling in the extremities, blurred vision, deafness, lack of muscle coordination and intellectual impairment, as well as adverse effects on the cardiovascular, gastrointestinal and reproductive systems. Prenatal exposure may interfere with fetal development of the central nervous system and cause neurological and developmental delays. Women who are exposed to methyl mercury and breastfeed may also expose the child through the milk.

Preliminary results from the Canadian Health Measures Survey taken in 2008/09 show that the geometric mean blood mercury level of Canadians aged 20 to 79 is 0.91μg/L. Fewer than 1% of Canadians have total mercury concentrations above the current Health Canada blood guidance value of 20 μg/L established for the general adult population.However, there is some controversy at how these maximum tolerable levels are established. Because mercury can be toxic at any concentration, some experts maintain that the blood guidance value should be ten times lower, or 2μg/L. If this were the case, more than 10% of Canadians suffer today from potentially toxic levels of mercury. How do mercury releases end up in our bodies and what can we do to avoid it?

Mercury that is released into the environment may be deposited into water where microorganisms can convert it to methyl mercury, a highly toxic form of mercury that can build up, or bioaccumulate, in living tissue. Small organisms and plants take up mercury as they feed and this mercury tends to accumulate in their tissues. As larger animals, higher up the food chain, consume these plants and organisms, methyl mercury is bioaccumulated at a more concentrated level. The process continues as you move up the food chain, with levels of mercury increasing in larger, predatory species. This process is known as biomagnification.

It's not all bad news, however. The liver can and does detoxify our system from this and other metals, so long as we do not load our bodies with too much mercury. Many studies have been made measuring the amount of mercury found in different species of fish. There are many kinds of fish that are very low in this harmful metal and can be eaten and enjoyed several times a week without risk of bioaccumulation, namely, flounder, haddock, ocean perch, salmon, sardine, scallop, shrimp, sole and tilapia. This list is not exhaustive. If you don't see your favourite I recommend that you look it up and confirm how often you can safely eat it. In this way, you can be sure that your natural detoxification system is eliminating this toxic metal faster than you may be ingesting it.

Finally, one last comment which could indeed save your life: Mercury vapours are extremely toxic. If you accidentally break a fluorescent light (or a CFL), you must leave the area immediately and ventilate the room for about 15 minutes. Only then will it be safe to return to clean up the mess. Do not touch the broken pieces, simply sweep everything into a thick garbage bag and dispose at a hazardous waste centre.

The sunscreen controversy heats up

Last summer I wrote about the sun and that we must judge just how much we allow it to shine on our exposed skin. I then alluded to the sunscreen controversy. One year later, the controversy continues. Let me explain:

Sunscreen protects against two common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma. However there is some evidence that several common sunscreen ingredients (namely, oxybenzone, benzophenone, octocrylene and octyl methoxycinnamate) may be linked to increased risks of malignant melanoma, a rarer but more deadly form of skin cancer. Other common sunscreen ingredients (namely, octinoxate and homosalate) are potential hormone disrupters.

Remember, too, as discussed last year, sunscreen use has been linked to vitamin D deficiency. Why is this important? Because there are indications that vitamin D deficiency may lead to skin cancer. Confusing, isn't it? We use sunscreen to reduce our risk of skin cancer, and then we learn that we may not be getting enough sun which our skin needs to produce the sun vitamin. In fact, vitamin D is produced in our skin after exposure to ultraviolet B (UVB) light. After some processing by our liver and then kidneys, this vitamin will defend our bodies against microbial invaders and also promote the healthy mineralization, growth and remodeling of bone. Finally, vitamin D also reduces inflammation (which we discussed last month).

The Environmental Working Group, an American watchdog on public-health issues, recently reviewed 1,755 sunscreens and found that only 8 percent blocked both UVA and UVB radiation, while also being free (or nearly free) of ingredients with known or suspected health hazards. Both UVA and UVB radiation from the sun (and tanning beds) can cause skin cancers after too much exposure, however for some reason most sunscreens only protect against the less harmful UVB radiation, and not against the more dangerous UVA component of the spectrum.

We can summarize the areas of concern:

• Potentially dangerous properties of some sunscreen ingredients
• Vitamin D deficiency caused by reduced exposure to ultraviolet light
• Incomplete protection against the full ultraviolet spectrum combined with increased time spent in the sun

There have been many sun exposure studies involving thousands of people over the past decade. Possibly due to the many kinds of sunscreen used, the amounts of sunscreen used, the self-reporting involved in most studies and the different countries (at varying latitudes) in which the participants lived, the results have often been contradictory if not inconclusive. Some show that use of sunscreen increases some forms of skin cancers while others show that their use reduces other forms of skin cancer, thus the controversy.

Here's my recommendation for staying healthy:

• Purchase sunscreen judiciously: it must block UVA and UVB radiation and contain none of the suspect ingredients.
• Use SPF 30 - SPF 50, those above SPF 50 have negligible extra benefit.
• Apply liberally when you expect to be in the sun for more than ten or fifteen minutes, especially at midday.
• Where a hat.
• Take a vitamin D supplement daily.
  

Finally, remember to give additional consideration to your lips. They are also at risk of painful burns and worse, lip cancer, too. Fortunately, safe lip sunscreens are available and should be purchased using the same considerations as outlined above for your skin sunscreen.

How to cure a sports injury

I always chuckle when I see an advertisement for a new and improved laundry detergent. I know that even as this product is being hyped as the best under the sun, it will next year be relegated to the rubbish pile. Then, the newer and improved detergent will again be 25% more effective, producing brighter colours, etc.
I feel the same way about first aid for sports injuries. One year we are told to quickly apply heat then ice; the next year it's ice for 48 hours then heat for 48 hours; lately we are advised to alternate between heat and ice every 2 hours for 24 hours. Last year's surefire solution is replaced by this year's new and improved remedy.
Here's what I read on a popular Internet site: "Applying ice to a soft tissue injury can help reduce swelling and inflammation by reducing blood flow to the injured area. Ice also provides temporary pain relief after an acute or traumatic injury. In order to get the best result, it's important to ice the injury during the 48 hours after the injury, before the swelling becomes advanced."
Why would you want to reduce swelling and inflammation anyway? Why reduce the flow of blood just when it is most needed? What causes inflammation and is it good for us or not?
Inflammation is the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli as well as initiate the healing process for the tissue. In the absence of inflammation, wounds and infections would never heal and progressive destruction of the tissue would compromise the survival of the organism.
After reading this formal definition, it may seem as clear to you as to me that acute inflammation is just what we need after an injury (chronic inflammation is another issue). Our bodies probably developed this inflammation response over millions of years of trial and error (if you believe in Darwin's theories of evolution). Any maneuver that an individual may attempt will necessarily interfere with this natural, protective response and in my opinion will always result in the injury taking longer to heal.
When we are injured, we absolutely want our bodies to heal quickly. It seems our bodies also want to heal themselves quickly as the resulting inflammation increases blood flow (which is why the injury turns red and feels warm) bringing the necessary nutrients to the injured site, and equally importantly, removing the cellular debris and other detritus away from the site. The area is tender and sometimes painful. Why? To remind us to rest the injured part and avoid physical stress. When the pain subsides, we can slowly start to use the injured area again. In this respect, pain is our friend, letting us know when we should take a break from activity or else risk further injury.
While we are discussing inflammation, you may be interested to know that there is a relatively unknown and hugely successful cure for many cases of chronic pain. It is called prolotherapy, short for proliferation therapy. Prolotherapy involves the injection of an irritant solution into the area where connective tissue has been weakened or damaged through injury or strain. Many solutions are used, including dextrose and lidocaine (a commonly used local anesthetic). The injection is given into joint capsules or where tendon connects to bone. Many points may require injection. The Injected solution causes the body to heal itself through the process of inflammation and repair. That is, the injected solution irritates the site, much like an injury does, which causes inflammation. Healing results naturally and permanently, even after years of suffering from chronic pain!
So please, do not apply ice to an injury, why add insult to injury?

Fiber - The ins and outs

The results of a study in teenagers were recently reported in the American Journal of Clinical Nutrition: Over the two-year study period, about half of the participants had decreased their consumption of fiber by an average of about 6 grams per day, while the remainder increased their fiber intake by a similar amount. The investigators were looking at belly fat, which is the most dangerous type of fat; fatter waistlines increase the risk of diabetes and heart disease. Belly fat increased 21 percent for the study participants who were eating less fiber, but the adolescents who upped their fiber intake had a 4 percent reduction in belly fat.

Separately, it was earlier reported at the University of Leeds that pre-menopausal women who eat 30 grams or more of fiber a day cut their risk of breast cancer by 52 percent. This study involved nearly 36,000 women and lasted over eight years.
I found these conclusions outstanding! So what's going on with fiber and our health? Exactly what is fiber anyway? What are the best sources of fiber and what are its health benefits?

Officially, fiber is a type of carbohydrate that the body can't digest. Great sources are whole fruits and vegetables, whole grain breads and breakfast cereals, and all manner of beans. The daily amount of fiber that is currently recommended depends on the number of calories that you consume each day. Most adult women should shoot for over 20 grams of fiber a day; teens and men should aim for over 30 grams.

Before discussing fiber's health benefits, let's first bust two myths:
1. All fiber is created equal. Not true. There are two basic types of fiber, with different functions. Insoluble fiber is found in wheat bran, nuts and many vegetables. Its structure is thick and rough, and it won't dissolve in water, so it zips through your digestive tract. Conversely, soluble fiber is found in oats, beans, barley and some fruits. It dissolves in water to form a gel-like material in your digestive tract. This allows it to slow the absorption of sugar into your bloodstream.
2. Fiber has no calories. Not true. Your small intestine can't break down soluble or insoluble fiber; both types just go right through you. That's why some experts say fiber doesn't provide any calories. However, this claim isn't entirely accurate. In your large intestine, soluble fiber's molecules are converted to short-chain fatty acids, which do provide four calories per gram, as with all carbohydrates. (Insoluble fiber has essentially zero calories.)

Finally, let's review a short list of fiber's health benefits and discuss the reasons for these benefits.

• Avoiding and relieving constipation. Fiber can absorb large amounts of water in the bowels, and this makes stools softer and easier to pass.
• Heart disease. Foods containing soluble fiber can have a positive influence on cholesterol, triglycerides, and other particles in the blood that affect the development of heart disease.
• Gallstones and kidney stones. Rapid digestion leads to a rapid release of glucose (sugar) into the bloodstream. To cope with this, the body has to release large amounts of insulin into the bloodstream, and this can make a person more likely to develop gallstones and kidney stones (in addition to diabetes and high cholesterol).
• Keeping Weight Under Control. Foods containing plenty of fiber have more bulk than low-fiber foods. Therefore, fiber can sometimes slow the onset of hunger because the contents of the stomach are bulkier and are retained longer. Here's a tip: avoid foods that have been made easier to eat by the removal of fiber, such as fruit juices. You would be far better off to eat an apple and then drink a glass of water, rather than having a glass of apple juice (which contains no fiber).

Indeed, the list of the health benefits of dietary fiber is much longer. It is safe to conclude that paying more attention to fiber may go a long way to improving your health and avoiding disease.

Obesity drugs -- panacea or fool's paradise

Despite years of research effort, the pharmaceutical industry has not made meaningful progress in combating obesity, arguably one of Canada's biggest and costliest health problems. The two existing obesity drugs, Meridia and Xenical have had limited success, with combined worldwide sales of under one billion dollars. Compare this with the annual sales of the statin drug, Lipitor, at 13 billion dollars.

Obesity in Canada is a growing health concern as it is one of the leading causes of preventable deaths. Canada ranks 35th on a 2008 list of fattest countries with a percentage of 61% of its citizens with an unhealthy weight.

In the last few weeks, three small American companies have completed clinical trials of the next wave of obesity drugs and will be considered for approval by the U.S. Food and Drug Administration. If approved, Canada will surely follow. These new drugs are called Contrave, Iorcaserin and Qnexa. In the last wave, when fen-phen drugs hit the market in 1994, prescriptions soared to 20 million in the U.S. alone, but by 1997 deadly side effects (to the heart) surfaced and the drugs were retired by their manufacturers in the face of huge lawsuits.

Clearly, both Canadians and Americans want a quick fix for losing weight. Is this possible? Will there soon be a free lunch?
Here's my take: The human body has evolved over hundreds of thousands of years in an environment somewhat different from the one in which we live today. Up until a hundred years ago, with the exception of pharaohs and kings, humans have had no alternative but to be physically active on a daily basis, just to survive. More recently, on the whole, we have become much more sedentary, and therefore many of us have thus become overweight, or so the statistics inform us.

But here's the problem with all drugs, including past obesity drugs and future ones, too. They introduce chemical formulations into the body that are foreign to us. Did you ever wonder why all drugs have side effects? It is because our bodies are very finely tuned organisms. While that foreign substance wrapped in a pill may result in one positive effect that we seek, it will surely affect something else inside us that may be dangerous or at least disruptive to our good health.

Let's look at the situation another way. After thousands of generations of unmitigated success as a species, our bodies expect the following ingredients to remain healthy, be strong to fight off germs and live a long life: Fresh air, pure water, natural fruits and vegetables, whole grains and nuts, and cooked fish, poultry and meat. Most everything else has the opposite effect: Robbing us of our good health and destroying our immune system.

In conclusion... there is no free lunch. Next month I will discuss a recent study which has surprising and counterintuitive conclusions that support my own beliefs: The only successful formula for losing weight and regaining strength is a change in lifestyle which promotes healthy habits, including physical activities, a proper diet and a positive mental attitude.

Fiber - The ins and outs

The results of a study in teenagers were recently reported in the American Journal of Clinical Nutrition: Over the two-year study period, about half of the participants had decreased their consumption of fiber by an average of about 6 grams per day, while the remainder increased their fiber intake by a similar amount. The investigators were looking at belly fat, which is the most dangerous type of fat; fatter waistlines increase the risk of diabetes and heart disease. Belly fat increased 21 percent for the study participants who were eating less fiber, but the adolescents who upped their fiber intake had a 4 percent reduction in belly fat.

Separately, it was earlier reported at the University of Leeds that pre-menopausal women who eat 30 grams or more of fiber a day cut their risk of breast cancer by 52 percent. This study involved nearly 36,000 women and lasted over eight years. I found these conclusions outstanding! So what's going on with fiber and our health? Exactly what is fiber anyway? What are the best sources of fiber and what are its health benefits?

Officially, fiber is a type of carbohydrate that the body can't digest. Great sources are whole fruits and vegetables, whole grain breads and breakfast cereals, and all manner of beans. The daily amount of fiber that is currently recommended depends on the number of calories that you consume each day. Most adult women should shoot for over 20 grams of fiber a day; teens and men should aim for over 30 grams.

Before discussing fiber's health benefits, let's first bust two myths:

1. All fiber is created equal. Not true. There are two basic types of fiber, with different functions. Insoluble fiber is found in wheat bran, nuts and many vegetables. Its structure is thick and rough, and it won't dissolve in water, so it zips through your digestive tract. Conversely, soluble fiber is found in oats, beans, barley and some fruits. It dissolves in water to form a gel-like material in your digestive tract. This allows it to slow the absorption of sugar into your bloodstream.

2. Fiber has no calories. Not true. Your small intestine can't break down soluble or insoluble fiber; both types just go right through you. That's why some experts say fiber doesn't provide any calories. However, this claim isn't entirely accurate. In your large intestine, soluble fiber's molecules are converted to short-chain fatty acids, which do provide four calories per gram, as with all carbohydrates. (Insoluble fiber has essentially zero calories.)

Finally, let's review a short list of fiber's health benefits and discuss the reasons for these benefits.

• Avoiding and relieving constipation. Fiber can absorb large amounts of water in the bowels, and this makes stools softer and easier to pass.
• Heart disease. Foods containing soluble fiber can have a positive influence on cholesterol, triglycerides, and other particles in the blood that affect the development of heart disease.
• Gallstones and kidney stones. Rapid digestion leads to a rapid release of glucose (sugar) into the bloodstream. To cope with this, the body has to release large amounts of insulin into the bloodstream, and this can make a person more likely to develop gallstones and kidney stones (in addition to diabetes and high cholesterol).
• Keeping Weight Under Control. Foods containing plenty of fiber have more bulk than low-fiber foods. Therefore, fiber can sometimes slow the onset of hunger because the contents of the stomach are bulkier and are retained longer. Here's a tip: avoid foods that have been made easier to eat by the removal of fiber, such as fruit juices. You would be far better off to eat an apple and then drink a glass of water, rather than having a glass of apple juice (which contains no fiber).

Indeed, the list of the health benefits of dietary fiber is much longer. It is safe to conclude that paying more attention to fiber may go a long way to improving your health and avoiding disease.

I've been trying for some time to develop a lifestyle that doesn't require my presence

Over the past half-year I have been writing about how the choices that we make every day about what we eat and how we exercise ultimately affect our state of wellness. These daily decisions, when grouped together, can be characterized as our lifestyle. Do we sleep enough, eat fruits and vegetables every day, enjoy our free time that we spend with friends and family? Or, are we sleep-deprived, eating too much junk foods or skipping meals altogether, and can't find the time to relax with our friends and family?
My belief has always been that the lifestyle that we choose does indeed determine our state of health and our chances of living a long life full of zest and joy.
In a recent edition of the Proceedings of the National Academy of Sciences, researchers from the University of Michigan reported some very counterintuitive findings: They looked at death rates during the Great Depression, the worst economic slump of the 20th century. From the stock market crash of 1929 through the early 1930s, economic activity fell sharply, dropping 14 per cent in 1932 alone.
Black and white images from the era of bread lines and migrant farmers make it easy to assume the economic misery would have affected public health. But when the researchers looked at mortality rates among men, women and children from 1920 to 1940, they found death rates declined during years of falling economic activity and rose when times were better.
And so it is with no surprise to the researchers that the same conclusions have already been drawn during the recent worldwide recession: When the economy gets sick, people get healthier. What's going on? How is this possible?
It seems that people adopt smarter lifestyles in recessions. People have less money to spend on alcohol and cigarettes. And less economic activity means people are working less, or not at all. Thus, they have more free time to go to the gym, or even for a walk. Exercise leads to weight loss, which in turn cuts down on the incidence of many maladies, particularly cardiovascular diseases. There's more time for sleep, which improves health. And with less money to spend, people drive less, which reduces pollution. Recent studies have linked particulate matter from cars and trucks and carbon monoxide with heart attacks and strokes.
A University of North Carolina study has found that a one-percentage-point rise in the unemployment rate reduces the death rate by 0.5%. Those are U.S. results, but other studies show the same effect in the 23 OECD countries in aggregate.
The recent downturn in dead people is a reminder that the No. 1 culprit for sickness and disease is lifestyle.
So, why wait for an economic downturn to become healthier? These statistics and studies support my very own enduring belief that the choices we make in how we live our lives determine our own health.
I am often asked for my opinion from friends on which foods are healthier, or which exercises give the quickest results, or how to lose weight and keep it off permanently. It is apparent that old habits are difficult to break and new behaviours are not easy to integrate into our daily routine. Ostensibly, most of us want to improve our health and happiness, but without a change in lifestyle, it doesn't seem to me possible. My response invariably is to choose one modification in behaviour, perhaps going for a half-hour walk every evening, learning a new sport, or attending a weekly lecture and then discover the enjoyment in this simple pleasure. Why not start 2010 off with a new commitment to enhancing your own lifestyle?