Fish oil capsules

Fish oil (Photo credit- ArtsieAspie)

Our diet supplies the basic building materials and energy that form the foundation for good health. As is commonly pointed out, over the last 100 years our diet has changed hugely from what would be considered a ‘natural’ human diet with increasingly severe effects on our bodies. Probably the two major changes in our diets have been the massive increase in sugar intake and the huge change in the types of fats we eat. In this post I want to touch briefly on the role of fat.

Research shows that the ratio of different fats that we eat is critically important. It seems likely that humans evolved on a diet that had about a 1 to 1 ratio of omega-6 to omega-3 essential fatty acids but over the last 100 years or so this ratio has changed dramatically to 15-16 to 1 (ie. we’re eating 15 times as much omega-6 as we are omega-3). In fact some studies put this ratio as high as 30:1.

It’s fairly certain that this massive change in our diet is contributing to many of the modern health epidemics- cardiovascular disease, cancer, autoimmune and inflammatory diseases have been linked to the ratio of essential fatty acids in the diet. It also seems likely that many of the health benefits of following a ‘Mediterranean’ or ‘Japanese’ diet come down to the fact that these diets have much better fat ratios that a standard western diet. Read More

Men runningI think it’s worth tackling this question on the blog because 1) I do get asked it fairly often and 2) it can serve as an example of how there really are no simple answers when it comes to health.

So… does running cause joint damage in your knees?

Well yes and no.

On the yes side it seems pretty clear that people who have been elite athletes have a much higher frequency of joint surgery/replacement for arthritis in their old age. This study shows that older males who were elite athletes in their younger days had a 60% higher rate of knee replacement and a 150% higher rate of hip replacement than their more sedentary counterparts. So that seems pretty clear. However this study which followed a group of long-distance runners for 18 years and compared them to non-runners over the same time period found no difference in joint degeneration on x-ray. The study authors conclude that “Long-distance running among healthy older individuals was not associated with accelerated radiographic osteoarthritis. These data raise the possibility that severe osteoarthritis may not be more common among runners”. These are just two studies of course but they represent the whole body of this research pretty well. I guess the most logical conclusion is that moderate running is generally fine for your joints but at the very high volumes and intensities of an elite athlete the stress on the joints becomes damaging.

So in order to answer the very straight-forwards question “Does running cause joint damage?” we have to take into account numerous different factors such as training volume and intensity, the athletes weight and body type, running style, body alignment, running surface, previous joint or muscle injuries, genetic susceptibility etc.

I guess the take home message is that- there are no simple answers for lots of our questions. Welcome to the wonderful and complex world of health!

And while I’m at it…

Is a red wine good for you? Yes and no.

Is yoga good for you? Yes and no.

Does stress make you sick? Yes and no.

Doesn’t this all make life too complex? Yes and no.

Picture of sunset from Waipu Cover

Evening light like this is good for your Melatonin levels (and good for your soul)

One of the true pleasures of the summer has been eating dinner on our deck and enjoying the long summer evenings.

Something that we take for granted is that modern life is largely lived indoors- but of course for most animals on the planet life is lived very much outside and even for us ‘human primates’ this is a very recent development in our evolutionary history. Of course living and working indoors is a pretty handy development for most of us but like all changes from our natural patterns it has some consequences.

One of the major effects is that we are partially removed from the natural rhythm of light and dark that helps to regulate our endocrine systems in their daily cycles. Living indoors means that we aren’t exposed to as much light during the day as we would be if we were largely outdoors and then using artificial sources of light in the evenings mean that we are exposed to more light in the evenings than we naturally would be. There is no question that this can significantly disrupt the way our brains and bodies function.

Here’s how the Neurology works: Our retinas have specialised cells (called ganglion cells) which aren’t used for vision but act to detect the intensity of the light passing through the eyes. These cells have nerve connections directly back to a part of the Hypothalamus gland (called the Suprachiasmatic Nucleus) this in turn controls the release of Melatonin from the Pineal gland. When you have a lot of light passing through your eye, melatonin release is suppressed – this makes you feel more alert. When you have low levels of light passing through your eye, the pineal is triggered to release more melatonin – and you feel sleepy.

Disruption of the natural cycle of melatonin can cause problems with sleep and consequent fatigue. Melatonin is also thought to play a role in conditions as diverse as cancer, immune disorders, cardiovascular diseases, depression, seasonal affective disorder (SAD), high cholesterol, obesity, anxiety, memory problems, and chronic fatigue syndrome. Melatonin is also an anti-aging hormone and has been shown to decrease age related degeneration and improve life expectancy in experiments on mice.

To help to regulate your melatonin production, think about when you are exposing yourself to bright lights. Research has shown that exposure to normal room light levels in the hours prior to sleep can reduce melatonin production by up to 50% resulting in difficulties falling asleep and less restful sleep. Also studies have shown that staring at a light source such as a TV or a computer screen in the evening supresses melatonin production. In one study participants who used a tablet computer for 2 hours in the evening had a 22% reduction in melatonin levels.

So what should we do about it?

Well electric lights and working indoors are here to stay but we should all be making an effort to get at least 30 minutes of natural light exposure every day and when we are inside we should keep things as light as possible.

Conversely, in the evenings try and dim the lights as much as is practical and turn down the brightness on your TV and computer screens. If sleep is an issue for you then you should definitely avoid bright lights and TV/computer screens for 90 minutes before bed.

Yes, that’s probably a slight inconvenience but I reckon it’s worth it for a refreshing night’s sleep.