Tag Archives: Gene

The Obesity Gene

Is there really an obesity gene? I think the answer is yes and no.  First the yes.

There are likely genes that predispose someone to being overweight or obese.  It is not just one gene but perhaps 10 or 50, or maybe 1,000.  I don’t think we will ever be able to say for certain what specific genes are the “obesity genes.” Certainly it is more difficult with something like this because metabolism is so complex.

The answer to our question might also be no.  While our genes are responsible for many things, the environment plays a huge role.  Diet and exercise are potent modifiers of our genes.  Someone who is genetically predisposed to being overweight may not be overweight with proper diet and exercise.  And if that’s true then, in a sense, being overweight is not genetic.

For more information watch the video below.

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Genes, Alzheimer’s Disease and Your Choice

PET scan of a human brain with Alzheimer's disease

Image via Wikipedia

New genes have been discovered that seem to be linked to Alzheimer’s Disease (AD).  AD currently affects over 5 million Americans and that number is expected to increase substantially by the year 2029.

This year the first baby boomers will reach their 65th birthdays. By 2029, all baby boomers will be at least 65 years old.  Ninety-five percent of all AD is in people 65 and older.

The discovery of new genes linked to AD is a step in the right direction.  Every bit of information that help scientists unlock the mystery of why this occurs puts us closer to being able to effectively treat AD.

Let’s pretend that we know every gene that is involved in the production of AD.  Let’s also pretend a test that exists to specifically detect all of these genes in you.  Would you want to find out?  What would you do if you had all of the genes linked to AD?

The truth of it is, there is nothing you could do to change your genes.  Your genes are your genes.  They are there and you can’t remove them.  What you can do, however, is change how they are expressed.  Just because a person has a specific gene does not mean it has to be expressed.  The expression of many of our genes is closely related to our environment.  Diet, exercise, smoking, pollution and stress are just a few things that can negatively or positively affect the expression of our genes.

So back to my first question.  What would you do if you had all the genes linked to AD?  You can’t change your genes, but you can change your risk factors.

There are many known risk factor that increase the risk of AD, independent of your genetic potential.  The number one risk is aging.  Unfortunately, there isn’t much that can be done about that.  We are all going to get older which is not necessarily a bad thing.  It is much better than the alternative!

Known risk factors for AD that are controllable are as follows:

You will notice that these risk factors significantly overlap with one another.  You will also notice that when you control one risk factor you will impact another.  If you can control these risk factors in your life you will significantly reduce your risk of developing AD regardless of your genetic potential.
Cardiovascular health is perhaps the most important.  Cardiovascular disease causes a chronic, low grade reduction in blood delivery to the brain.  This is known as hypoperfusion.  This hypoperfusion is responsible for protein synthesis defects that later result in the classic AD neurodegenerative lesions.

To keep your cardiovascular system as healthy as possible make sure you eat an anti-inflammatory diet and exercise.  Fish oil is also something you should consider.  Fish oil, which contains omega-3 fatty acids, has been shown to reduce cardiovascular disease mortality better than any other substance known.

Reduction of high blood pressure is also very important.  When blood pressure is too high it fuels a kind of scarring linked to later development of Alzheimer’s disease and other dementias.  Controlling your blood pressure is actually very simple.  You must maintain a healthy weight first and foremost.  This, of course, means diet and exercise.  Increasing waistlines mean more tissue and blood vessels for your heart to push blood through. This puts a strain on the heart and increases the resistance the heart must push against.

Keeping a healthy cholesterol profile is essential.  However, the traditional tests from your doctor are probably not enough to tell whether you are at risk or not.  Traditional tests examine total cholesterol, HDL (“good”), LDL (“bad”) and triglycerides.  These are of some value, but they don’t tell the whole story.  What you must find out is the particle size.  In a nut shell, large and buoyant molecules of cholesterol are not as problematic as small and dense particles.  Your traditional test does not distinguish between the two.  Your traditional test might look very good, but a more advanced test may show that you are still very much at risk.  See my blog entry from last summer for more detailed information.

Diabetes is also extremely important to control.  Some references are referring to Alzheimer’s as Type III diabetes because of the biochemical similarities. Even being borderline diabetic raises the risk of developing Alzheimer’s or dementia by 70%!  Diabetes’ hallmark is high blood sugar.  This high blood sugar leads to a phenomenon called advanced glycation end products or AGEs.  AGEs adversely affect the structure and function of proteins. In combination with oxidative stress brain function is easily affected.  Advanced glycation end products have been found to be much more prevalent in the brains of Alzheimer’s patients than in healthy controls. This process begins early on in the course of Alzheimer’s and there is also evidence that AGEs assist in the formation of plaques seen in AD.  Diet and exercise are the best ways to prevent diabetes and reduce your risk of AD.

While the study for a purely genetic link to AD will continue, a cure is likely many years away if one can even be found.  What we can control, however, are our lifestyle choices that activate our genes.  If we choose poorly, we are much more likely to activate unfavorable genes that cause disease.  If we choose wisely, we are more likely to activate genes that are favorable and reduce our risk of further disease.  The choice is yours.  Make the right one.

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FrankenSalmon – Genetically modified for whom?

It’s a good question.  Who benefits from genetically modified salmon?  Well for one, the company producing it does.

This fish in the back is genetically modified. The one in the front is a non-genetically engineered salmon of the same kind.

Financially, this would reduce the cost of farmed salmon.  And two, I suppose it would reduce the cost of farmed salmon in the supermarket.  That, however, is not a viable reason to genetically modify salmon because I never recommend people buy farmed salmon in the first place.

There has been a debate recently about the safety and use of genetically farmed salmon.  These salmon have been genetically modified to grow bigger and faster yet require 10% less food.  It’s called the AquAdvantage salmon.  It has genes inserted in it from its close cousin the Chinook salmon and from something called the pout fish.  The combination of this genetically engineered animal allows it to grow faster, larger and year round instead of just the warmer months.

This debate has made its way to the FDA who has yet to make a decision on whether to allow its sale.  So far all they have concluded is that “it is safe for human consumption.” I wouldn’t put a lot of stock in that because they also deem things like aspartame, artificial food dyes and high fructose corn syrup “safe for human consumption.”

There are several problems I see with genetically engineered salmon:

1. Environmental Impact

This is a biggie.  These salmon are not natural but they are farmed in natural environments.  They are farmed in the open ocean in huge nets that allow them to swim freely, more or less.  What happens when one escapes?  Millions of fish that are farmed in this manner escape every year.  They are sure to escape and because they are bigger and faster they will out compete the truly wild fish for everything from mates to food.  Then we will have genetically modified fish and non-genetically modified fish mixed together.  Why is this a problem?  Because the native salmon populations are already in danger and anything that could possibly eliminate them is a serious threat.  This qualifies.  It’s also problematic because our salmon population will no longer be pure.  No one can predict how nature will react and this is walking a dangerous line.

2. Is it safe to eat?

At this point, this is a question that remains unanswered.  I can say this though – an animal is born with a natural genetic code.  It has evolved over millions of years to operate best with that genetic code.  Changing that genetic code is potentially dangerous and could possibly have unknown consequences.  Genetic codes do change, that we know.  However, they do not change overnight as is the case with this new salmon.  They change over thousands of years and generation after generation is allowed to adapt.  We cannot possibly know what kind of impact allowing a fish to grow twice as fast will have on the quality of the meat or how it will affect it on a molecular level.  What if this rapid growth causes the production of an unwanted chemical within the muscle of these new fish?  What if that chemical, unknown to us, is dangerous the human health?  The possibility is there and it is dangerous.

3. Will you know you are eating this FrankenSalmon?

Should it be allowed for sale in the US, you will not be able to tell what kind of salmon you are eating.  Because the FDA says the genetically engineered salmon is not substantially different from regular salmon, AquaBounty wouldn’t be required to label it as genetically engineered.  This leaves us with basically no choice.  You could of course only consume wild salmon and you would be safe.  I always recommend this, but I am also a realist and know that it’s not always possible to get wild salmon everywhere you go.  This salmon will be farmed in Panama and currently it would be the only salmon farmed in Panama so under current labeling laws it would have to state that.  This may be another way to tell if it is genetically modified.  Unless something is done to make sure that genetically modified salmon are labeled as so, I fear people will be consuming them without knowing it and without a real choice in the matter.

These fish are actually siblings. The one in the front is not genetically modified, but the one in the back is.

Genetically engineering food is a slippery slope.  It opens up the proverbial can of worms.  Putting these fish into our food supply is a dangerous act and could lead to problems down the road in the environment and in human health.  At this point we simply do not know enough to safely put this into our diets.  Much more research and time needs to be dedicated to finding out whether this is safe for long term human consumption.

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“I’m destined to get (insert disease here) because my parents did.” – Maybe Not.

The field of genetics has rapidly evolved over the last 15-20 years.  The latest push in genetics is trying to figure out why some people with specific genes express them and why some do not.  For example, a very well-known gene is the “breast cancer” gene called BRCA.  This gene is known to increase the risk of developing breast cancer, but it’s not an absolute.  Just because you have the gene does not mean you are going to get breast cancer.  So why the difference?  Why would one woman with the gene get breast cancer and the next not?

Well some new research on vitamin D may help us find out.  It is clear that vitamin D is a potent genetic regulator.  The reduction in cancer rates and the rates of other diseases drops sharply with adequate vitamin D levels.  Most people, however, do not have adequate levels of vitamin D.

Vitamin D is considered a vitamin, but it’s really a hormone.  It is best obtained from direct sunlight but dietary sources do exist and include fortified milk, eggs and oily fish.  Vitamin D is probably best known for helping people build and maintain strong bones.  While it is essential for that, the story for vitamin D only begins there.

Vitamin D is believed to have a role in controlling genes linked to major diseases such as certain types of cancers, dementia, and autoimmune disorders, new research has found.

“Through large scale studies, we now have a good idea of the genes involved in common complex diseases such as type 1 diabetes, multiple sclerosis and systemic lupus erythematosus,” wrote lead author, Dr. Sreeram Ramagopalan of the Wellcome Trust Centre for Human Genetics at Oxford University.

Scientists from University of Oxford, The London School of Medicine and Dentistry and Simon Fraser University in Canada identified 2,776 gene positions occupied by the vitamin D receptor and 229 genes that changed in response to vitamin D.  That’s right, thousands of genes respond to vitamin D.  To put this in perspective, the human genome has an estimated 23,000 genes.  That means vitamin D has a direct effect on over 12% of our genes. It doesn’t get more important than that!

What I want to stress is that if you are concerned about a part of your family’s health history as it relates to you (and who isn’t) taking vitamin D is good insurance.  It may just offset your genetic potential for disease by controlling your genes and keeping the bad ones turned off and the good ones turned on.

How much should I take?

I always recommend that my patients have their serum vitamin D checked.  It has become a very routine test for physicians to order and just about every person who comes to see me walks out of my office with a lab requisition to check vitamin D.

Taking vitamin D is simple.  Most people, even ones in sunny climates, can benefit from taking vitamin D.  Here in the Northeast I recommend my patients take 4,000-6,000 IUs per day for maintenance.  If we are working to significantly raise serum levels a dose of at least 10,000 IUs per day is necessary.  The point is check your blood levels.  Shoot for a level of between 55 and 65 ng/ml.  Once you reach that level you must maintain it to continue to get all the benefits that vitamin D provides.

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