Does the Blood Type Diet Really Work?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues

Is Eating Right For Your Blood Type A Sham?

Author: Dr. Stephen Chaney

cb43e76f-6bf7-4e82-8fc1-95005d2c5626Does the Blood Type Diet really work? In 1997 Dr. Peter J. D’Adamo wrote a book about the blood type diet called “Eat Right 4 Your Type”. Dr. D’Adamo claims that people with different blood types process food differently, so their blood type determines the type of diet that is healthiest for them. Specifically, he claims that people with:

  • Blood group O are descended from hunters and should consume high protein diets.
  • Blood group A are descended from farmers and should consume a near vegetarian diet – completely avoiding red meats.
  • Blood group B are descended from nomads. They have the most flexible digestive system and can eat the widest variety of foods – even dairy products, which he does not recommend for any of the other blood types.
  • Blood group AB are an enigma and are somewhere between blood group A and blood group B.

It’s an interesting concept. Dietary recommendations are made for populations as a whole, and there is tremendous genetic variation in populations. Because of that genetic variation, there is no perfect diet for everyone. Every knowledgeable health expert will tell you that.

The question then becomes “How do you know what kind of diet is healthiest for you?”

The blood type diet is a very simple system. Your blood type is easy to determine. Once you know your blood type you know what to eat. There’s no guesswork.

Could it really be so simple? Over 7 million copies of Dr. D’Adamo’s book have been sold. Millions of people believe in this concept. So it is only fitting to ask “What is the evidence?”

An Objective Scientific Analysis of the Blood Type Diet

There is no doubt that blood type is related to some human genetic and physical traits, but the important question is whether blood type is related to the health outcomes of different diets – the central thesis of Dr. D’Adamo’s book. A Belgian group lead by Dr. Emmey De Buch did a systematic search of the scientific literature to answer that very question (L. Cusack et al, Am J. Clin. Nutr. , 98: 99-104, 2013).

They identified 1415 scientific articles that had the phrase “blood type diet” in either the title or abstract. Then they begin the elimination process. They eliminated:

  • Studies done in test tubes, cell culture, or animals. Only human clinical studies were included.
  • Reviews, commentaries, letters or opinions. Those contained no original scientific research.

At this point they were down to just 16 published clinical studies. Then they asked which of those studies were designed to test the central hypothesis of the blood type diet. They asked:

  • Did the study start with human subjects grouped according to blood type?
  • Did the study have an intervention in which the subjects were required to adhere to a particular type of diet?
  • Did the study measure a health outcome of the dietary intervention?

Guess what? Only one study met these criteria. Just one! And it was a fairly weak study involving a totally different blood typing system than the ABO blood groups.

The Bottom Line:

1)     There is no scientific evidence supporting the blood group diet. A lot has been written about the diet, but nobody has actually shown that it works. The Emperor Has No Clothes!

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Latest Article

Does The FODMAP Diet Reduce Gas and Bloating

Posted July 26, 2016 by Dr. Steve Chaney

Author: Dr. Stephen Chaney

 

fodmap dietCan the FODMAP diet help reduce gas, bloating, diarrhea, and constipation? Everyone suffers from one or more of these symptoms, but nobody talks about them. For some they represent an annoyance. For others they can be incapacitating.

When the symptoms become frequent and start to affect quality of life, the medical community starts to give them names. When the symptoms occur at least 3 days/month for at least 3 months and there are no known diseases causing the symptoms, it is called irritable bowel syndrome (IBS). If the symptoms are also associated with inflammation, it is called inflammatory bowel disease (IBD). The principle forms of IBD are Crohn’s disease and ulcerative colitis.

A Primer On IBS And IBD

IBS is fairly common. Between 10-15% of the US population has been diagnosed with IBS, but experts estimate that as much as 25% of the population experiences symptoms consistent with IBS.

It is also important to understand that IBS is a collection of symptoms, not a disease. The only difference between IBS and the gas, bloating, and diarrhea (or constipation) that many people experience on a fairly regular basis is the frequency and severity of symptoms – and that is an arbitrary distinction. Someone experiencing those symptoms an average of 2 days/month is not significantly different than someone experiencing those symptoms 3 times/month.

While severe IBS can be incapacitating, it does not appear to cause lasting damage to the intestine or predispose to other diseases. Finally, the causes of IBS are largely unknown. Stress, obesity, and food sensitivities may all play a role.

IBD is much less common (0.4% of the US population), but much more severe. It can cause permanent damage to the intestine and can predispose to several diseases, including cancer. For that reason, you should always consult with your physician if you have severe, chronic gastrointestinal issues.

Standard treatment of IBS and IBD has traditionally consisted of recommendations to:

  • Reduce weight if overweight
  • Increase exercise
  • Reduce stress
  • Limit caffeine and alcohol
  • Limit fatty foods
  • If diarrhea is the primary symptom, limit dairy products, fruits, and sweeteners such as sorbitol and xylitol.
  • If constipation is the primary symptom, increase dietary fiber

These interventions generally provide only partial relief of the symptoms, so medications are frequently prescribed to control the symptoms. Unfortunately, many of those medications have significant side effects.

Fortunately, research over the past decade suggests that there is a natural, holistic approach that can significantly reduce the symptoms associated with IBS and IBD, thus decreasing the reliance on medications to treat those diseases. It is something called the FODMAP diet. The FODMAP diet is rapidly becoming the standard of care for IBS and IBD, and the same diet also appears to significantly improve symptoms in people who merely experience gas, bloating, and diarrhea more frequently than they would like. More importantly, the principles behind the FODMAP diet can help almost everyone who experiences occasional gas, bloating, diarrhea and/or constipation.

What Is The FODMAP Diet?

The FODMAP diet was devised over a decade ago by a group of scientists in Australia. Basically, they identified all of the kinds of foods that were known to cause gas, bloating, diarrhea, and/or constipation in susceptible people and put together a diet that was low in all of them.

FODMAP is an acronym that stands for:

  • F – fermentable carbohydrates
  • O – oligo-saccharides
  • D – di-saccharides
  • M – mono-saccharides
  • P – polyols

Of course, that statement comes under the “Aren’t you glad you asked?” category. It is meaningless to most people. A better way to understand this is to look at foods in the FODMAP category. They include:

  • gas and bloatingLactose, found in milk and milk products (especially for people who lack the enzyme lactase)
  • Fructose in high concentrations, found in foods like apples, pears, honey and agave syrup. (30-40% of individuals have problems absorbing fructose).
  • Fructans, found in foods like wheat, onions and garlic.
  • Galacto-oligosaccharides, found in foods like beans, lentils, and soybeans.
  • Polyols such as sorbitol and mannitol, found in fruits such as cherries, apricots, and apples, and as sweeteners added to many “sugar-free” foods.

These are all foods that are poorly digested or poorly absorbed, so they are fermented by intestinal bacteria. It is the fermentation of these foods by intestinal bacteria that causes the gas, bloating, and diarrhea.

Does The FODMAP Diet Work?

The evidence that the FODMAP diet is effective is pretty impressive. For example:

What Does This Mean For You?

On the surface, this seems to be a good news, bad news story.

good news bad newsThe good news is that the FODMAP diet is incredibly effective at decreasing frequent gas, bloating, abdominal discomfort, diarrhea and constipation – and it really doesn’t matter whether you have been diagnosed with IBS or IBD, or you are just someone who suffers from those symptoms more frequently than you would like.

The bad news is that the FODMAP diet is very restrictive. You can appreciate that when you look at the list of high FODMAPs foods you need to avoid. That means:

  • The diet is very difficult to stick to long term. In the follow up study described above only 30% of the participants were able to stick with the diet for the full 16 months.
  • The diet restricts so many foods that you would really need the guidance of a registered dietitian to design a nutritionally adequate diet plan.

 

The reality, however,is that very few people actually need to restrict all the high FODMAP foods to enjoy significant relief from their symptoms. Clinically, most physicians test various FODMAPs in their IBS and IBD patients and only restrict the ones that cause symptoms. You can do exactly the same thing yourself. Start by reducing groups of high FODMAP foods on the list. Once you have identified which food groups cause your symptoms, you can test foods within that group one by one.

The most important news is that the FODMAP diet concept may help many people who struggle with occasional gas, bloating, and diarrhea. Let me give you one example:

  • Let’s suppose you have discovered that foods made from wheat flour cause you g.i. problems. You have concluded that you are gluten intolerant and carefully avoid foods containing gluten, but you still have occasional gas, bloating and diarrhea. You might be sensitive to the fructans in wheat, not the gluten. If so, a quick glance at the FODMAPs list suggests a number of fructan-containing foods you may be sensitive to that you would never have expected if you just focused on avoiding gluten. For example:
  • Vegetables: garlic, onions, asparagus, artichokes and snow peas might be causing you trouble.
  • Fruits: grapefruit, nectarines, plums and watermelon could be causing you problems.
  • Processed foods: Inulin, a naturally occurring fiber, found in Jerusalem artichokes, is primarily a fructan. Inulin and several other naturally occurring fructans are added to many processed foods to increase their fiber content. These foods might also be causing you trouble.

This is just the tip of the iceberg. Most of us have probably identified one or two problem foods that we know give us gas. By using the FODMAPs list we may be able to identify other foods we should avoid.

 

The Bottom Line

  • By restricting all foods known to cause gas, bloating, diarrhea and constipation in susceptible individuals, scientists and clinicians have created something called the FODMAP diet.
  • The FODMAP diet has proven to be very effective at reducing those symptoms in people with IBS or IBD, but it is also equally effective at eliminating symptoms in individuals who simply suffer from gas, bloating, abdominal pain, diarrhea and/or constipation more frequently than they would like.
  • The low FODMAP diet is also very restrictive, but the good news is that most people don’t need to eliminate all of the foods in the diet. You can systematically test and eliminate the individual foods that cause your symptoms.
  • Most importantly, the FODMAP concept can help us identify problem foods that we might have otherwise never suspected of giving us gas. You will find an example of how this concept works in the article above.
  • Gas, bloating, abdominal pain, diarrhea and constipation can also be caused by a number of serious diseases. For that reason, you should always consult with your physician if you have severe and chronic gastrointestinal issues.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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