Vitamin D and immunity

Vitamin D and immunity

Vitamin D is essential for life without it we perish. It is required for thousands of metabolic reactions and acts as a spell checker on our DNA. Just about every modern Western disease is associated with it’s deficiency. Most people are aware that we need it for bone health but it is essential for so much more.

We need it for the functioning of a competent immune system. Without it we are more likely to succumb to viral infections. In one Spanish study of patients admitted to hospital (with our current viral menace) significantly avoided going to the ICU if vit D was given. Although the study has been dismissed for being small it was statically significant.

Ideally we need to make it from the sun. Many other compounds are produced by the sun in the skin than science has yet to document. For instance nitric oxide is produced as a result of exposure to UVA and drops our blood pressure. Being in the sun makes us feel great and gives us a shot of endorphins. Were nature discouraging us from being in the sun I doubt she would give us such a reward.

However, excess sun exposure can be a hazard to our health. There is a sweet spot. I use an app called Dminder which takes into account skin type, UV, latitude and altitude. It then calculates the safe duration of exposure. It’s free and well tested. Give it a go!

Sugar 101: Digestion of starch

When I was at college I had the most amazing biology teacher. One day she brought in a beautiful loaf from Cranks-an up market whole foods restaurant in England. It was artisan, wholegrain, organic and made from sour dough. At that time there were test papers that on contact with glucose turned violet. She gave us one each and cut the loaf into 32 pieces for her pupils.

Then she instructed us to chew the piece of bread for 20 seconds. We put the paper on our tongues. It turned violet. This showed us that even in the mouth there are amylases, that is enzymes, that actively break down starch into it’s basic building blocks-glucose. This continues in the gut after we swallow.

Starches can raise our blood sugar very quickly. Rice cakes, which many consider to be a health food, do it more quickly than sucrose ie. table sugar. Foods are graded in terms of their glycemic index or the speed and extent they raise blood sugar. Portion size also has an effect.

We have 7 pints of blood on average. I often ask my patients how much glucose they think is circulating in their blood stream. Invariably they say things like 1-2 pints or 500 grams. The real figure is near to 5 grams. That is just a teaspoon of glucose in 7 pints of blood. When we eat something like a ripe banana we are taking on 6 teaspoons of sugar. A 150 gram serving of potatoes is the equivalent of 9 teaspoons of sugar.

It is not just the obviously sweet foods that are a problem. Starches that do not taste sweet are very readily digested into simple sugars.

Common foods can wreak havoc metabolically without our knowing. One way to find out how foods are affecting our blood sugar is to use a continuous glucose monitor. The monitor is attached to the upper arm for two weeks and the patient can, without using a lancet, measure their blood sugar with an app on their phone. They can then discover which foods are causing blood sugar excursions. This gives them valuable information. They are then able to make informed dietary changes that prevent future disease.

Sugar 101: Starch, insulin resistance and diabetes.

Long before we express the symptoms of type 2 diabetes (DM2) there are often years of poor metabolic health. This can be asymptomatic and we may unwittingly consider ourselves to be healthy. Only 12% of the US population is normal from a metabolic perspective. Most people are sick. Sugar and carbohydrates that make up a lot of the processed foods we eat cause our blood sugar to oscillate. The peaks stimulate a panic as the body wants to keep blood sugar in a narrow healthy range. Insulin is produced by the pancreas, this encourages the sugar into the cells and out of the blood stream.

Once the cells are swamped with sugar they are increasingly reluctant to take on any more. They start to resist the action of insulin. As a result the body responds by producing even more insulin to over come the resistance. This becomes a vicious cycle of increasing insulin resistance on the part of the tissues and excessive insulin from the pancreas.

The body can also overshoot with insulin leading to low blood sugar (hypoglycemia). This makes us feel ‘hangry’ as stress hormones such as cortisol and adrenaline are released in a desperate bid for the blood sugar to be raised. These hormones can make us feel panicky and anxious which is why I remove foods that destabilise blood sugar from my anxious patients.

Over time if we continue to eat more sugar than the body can cope with insulin becomes ineffective and blood sugar starts to rise. Once our HbA1c is >6.4% our doctor diagnoses DM2. (HbA1c is a protein that picks up how much sugar has been in the blood over the last three months). The solution to the problem; lifelong medication.

Once we become insulin resistant we can no longer respond well to carbohydrates across the board. Now even starches are a problem. Glucose is a monosaccharide that can form long strings of itself. These are commonly referred to as starch. So be it rice, grains, potatoes or pasta you are basically eating sugar. A 150 gram bowl of rice is equivalent to eating over 10 teaspoons of sugar. Fancy a chunky sandwich? That’ll be 12 teaspoons of sugar. It is not just the foods that taste sweet that are a problem but the foods that become sugar when broken down by our digestion.

There are other contributors to insulin resistance apart from sugar and starch such as vit D deficiency. I will explore these other factors in future posts.

Sugar 101 : Fructose is not your friend.

Our ability to refine sugar on a mass scale is from an evolutionary perspective very recent. Sugar was first produced in India some 2,5000 years ago and was a rare spice originally only affordable by the aristocracy. The technology that enabled industrial production was not established until the 19th century. In 1700 the average person consumed just under 2 kgs per year, by 1800 this was 10.2 kgs, by 1900 40.8kgs and in 2009 81.6kgs (USA).

Fructose is the sweetest of the sugars and is the one we would have sought out in nature. It is a five sided sugar and has, in excess, an effect on the liver similar to that of alcohol (but without the fun). It is problematic in that most of the cells of the body cannot use it for energy. It combines with our tissues turning them to toffee. This process is called glycation. Only the liver can begin it’s metabolism. Glucose, by comparison, is taken up by most of the cells and can be used directly for the generation of energy. Too much fructose or other sugar can cause the liver to become fatty. Left unchecked this can develop into cirrhosis and eventual liver failure.

Humming birds take advantage of this fatty liver mechanism. They drink fruit nectar during the day and the liver becomes creamy white with fat. At night due to their extreme metabolic needs this is reversed. Sadly in a lot of modern humans we eat so much high fructose corn syrup (HFCS) that the liver has no rest. We never fast long enough to let the liver release the fat and are continually assaulting it with simple carbohydrates. Sugar is added to over 70% of the food in the supermarket.

This is a historically bizarre situation. If sugar was introduced as a new substance now it would not pass safety standards and would be banned alongside heroin, morphine and cocaine. When we ingest it our brains are activated by endogenous opiates and dopamine. This gives us a sensation of pleasure. In the past, prior to agriculture, this hit would have usefully spurred us to eat fruit. No foodstuff in nature is at once sweet and immediately poisonous. That sweet taste is a reassurance of safety. In nature however fruits are not present all year round. The original fruit cultivars are so far removed from the modern ones it is like comparing a wolf frankly with a chihuahua.

So why is this addictive poison still in the food supply? Could it be that there are vested interests? After all there is far more money to be made from the sick than from the healthy. HFCS is cheap, an excellent preservative and is super sweet. On the one hand we have a poisonous, addictive food supply that makes us sick. Then the pharmaceutical industry sells us expensive drugs so we can carry on eating this rubbish. Kerching!

Want to know more? Enjoy this classic lecture from Dr Lustig UCSF.