Heart Disease & TMAO: Is a Vegan Diet Necessary?

In summary: Most of the studies seem to be surveys ... people keeping track of... something.In summary, the article discusses how the culprit in heart disease goes beyond just the fat on red meat. The researchers suggest that a little-studied chemical called TMAO is the root of the problem and that not eating red meat also has um side effects. It seems that the science behind the article is inconclusive, with different reports coming out every month.
  • #1
Simon Bridge
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Come to my attention vie the NYT article:
Culprit in Heart Disease Goes Beyond Meat’s Fat
... The researchers had come to believe that what damaged hearts was not just the thick edge of fat on steaks, or the delectable marbling of their tender interiors. In fact, these scientists suspected that saturated fat and cholesterol made only a minor contribution to the increased amount of heart disease seen in red-meat eaters. The real culprit, they proposed, was a little-studied chemical that is burped out by bacteria in the intestines after people eat red meat. It is quickly converted by the liver into yet another little-studied chemical called TMAO that gets into the blood and increases the risk of heart disease.

The paper seems to be:
Koeth R. A., Wang Z. et al. http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.3145.html Nature Medicine (2013) doi:10.1038/nm.3145

So it appears we should be adopting a vegan diet or take antibiotics with our steak?
My reading of what I can follow is that everything is very iffy still... the researchers have proposed another mechanism that may link red meat to heart disease that differs from the previously supposed mechanism.

Presumably not eating red meat also has um side effects?

What is this really all about? Is the science reporting over-hyped again?
 
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  • #2
Simon Bridge said:
Come to my attention vie the NYT article:
Culprit in Heart Disease Goes Beyond Meat’s Fat
... The researchers had come to believe that what damaged hearts was not just the thick edge of fat on steaks, or the delectable marbling of their tender interiors. In fact, these scientists suspected that saturated fat and cholesterol made only a minor contribution to the increased amount of heart disease seen in red-meat eaters. The real culprit, they proposed, was a little-studied chemical that is burped out by bacteria in the intestines after people eat red meat. It is quickly converted by the liver into yet another little-studied chemical called TMAO that gets into the blood and increases the risk of heart disease.

The paper seems to be:
Koeth R. A., Wang Z. et al. http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.3145.html Nature Medicine (2013) doi:10.1038/nm.3145

So it appears we should be adopting a vegan diet or take antibiotics with our steak?
My reading of what I can follow is that everything is very iffy still... the researchers have proposed another mechanism that may link red meat to heart disease that differs from the previously supposed mechanism.

Presumably not eating red meat also has um side effects?

What is this really all about? Is the science reporting over-hyped again?
I just read (a month ago) a study that red meat is not harmful because stearic acid isn't bad for you. It's the same type of spin they use for coconut oil, even though it's a highly saturated fat it has a dab of good fat. Now does that mean that dab of good fat makes it healthy? No! But marketers want you to think it does.

You really have to look long and hard at what the studies are saying. If something is 90% bad, 10% of something good in it does not make it healthy. It seems every new study contradicts the last. Maybe this is a new career opportunity, interpreting what nutrition studies really mean.
 
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  • #3
Simon Bridge said:
Presumably not eating red meat also has um side effects?
This is anecdotal, but I went without eating any kind of meat for ten years and did not notice any difference of any kind except a tendency toward less body fat.

The only risk I know of is that, if you don't make up for it from other sources, your iron levels may become too low and you'll become anemic.

http://www.irondisorders.org/iron-deficiency-anemia
 
  • #4
I've heard there are long term effects - iron deficiency being one, and vitamin B12 deficiency being another, with women being more susceptible than men. I've also heard that humans don't make taurine so well either so we need small amounts in our diet.

The article compares red meat eaters with those on a vegan diet.

What I'm mostly interested in is what the actual science is behind the article.
It seems that every day someone is telling me that some common food is terrible in some way and backing it with some luck-warm science that managed to get published someplace that doesn't really say so much.
 
  • #5
I know what you mean Simon. It seems that contradictory reports come out monthly. Sometimes I notice that the outcome comes out in favor of the source doing the funding.
 
  • #6
Or in favor of some pet fad or something on the part of the researchers ... the comparison to veganism raised an alarm bell on this one for that reason: why pick vegan diet? Why not some other vegetarian diet? What about finding people who only eat white meat?

"maybe a targeted antibiotic" though, suggests the researcher is fishing for funding.

Most of the studies seem to be surveys ... people keeping track of their diet and stuff like that.
Many are qualitative at heart - at least this one measures something.

The actual research appears to just notice that people who are used to eating meat produce more of substance X than people who are not ... and this is of interest because other studies show a corellation between substance X and heart disease in rats.

This is supposed to support a conclusion that substance X is the main cause of heart disease in humans.
I don't think the evidence presented is good support for the conclusion ... but it is the press that is emphasizing the conclusion isn't it?

But it is well outside my field so I may be reading it wrong.
 
  • #7
back around 1980 I read this book
https://www.amazon.com/dp/0394480112/?tag=pfamazon01-20
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and saw myself .

In 1995 at age 48 I went to ER with a heart attack. Flatlined for the ER folks but they got me going again. As they wheeled me out of ER one of the medics asked: "You're not overweight, you don't smoke and don't drink, you are cracking jokes and seem lighthearted - why are you here?
I responded quite honestly "I'm a closet type A". They immediately burst into unanimous agreement "That'll do it"...
A couple days later they ran the angiogram scans. My three arteries were 70, 90, and 100% blocked.
My co-workers were amazed - I was known as the "health nut" who ate salads for lunch.

Those two surgeons who wrote that book are on to something.
They say stress changes how we metabolize cholesterol.
It's not what you eat, it's what's eating you.
Something has to be pretty true to achieve platitude status.

So does this TMAO affect how we metabolize cholesterol?

http://en.wikipedia.org/wiki/Trimethylamine_N-oxide
TMAO alters cholesterol metabolism in the intestines, in the liver, and in artery wall. In the presence of TMAO, there is increased deposition of cholesterol in, and decreased removal of cholesterol from, peripheral cells such as those in the artery wall.[8] Vegans and vegetarians appear to have fewer gut bacteria that convert carnitine to TMAO.[9][10]
How about worry-warts ?

A quick search on 'TMAO stress' turned up some studies on heat stress in sharks but I don't understand them.
But I am interested so will keep an eye out for more.

Thanks for the alert, guys.
 
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  • #8
It is well known that stress kills - stressing out about your diet will do it too.
IIRC the "type A - type B" personality type idea has been debunked but it remains a useful metaphor.

So what we are saying is that TMAO is a plausible main-contributor anyway?
That would be a serious buzz-kill for those "paleolithic diet" people then wouldn't it?
 

1. What is TMAO and how is it related to heart disease?

TMAO (trimethylamine N-oxide) is a compound produced by gut bacteria during the digestion of certain nutrients, such as choline and carnitine. High levels of TMAO have been linked to an increased risk of heart disease, as it promotes plaque formation in the arteries.

2. What role does a vegan diet play in reducing TMAO levels?

A vegan diet, which eliminates all animal products, is naturally low in choline and carnitine. This means that there is less material for gut bacteria to produce TMAO from, leading to lower TMAO levels in the body. Additionally, plant-based foods contain beneficial nutrients and antioxidants that can help protect against heart disease.

3. Is a vegan diet the only way to reduce TMAO levels and prevent heart disease?

No, a vegan diet is not the only way to reduce TMAO levels and prevent heart disease. Other dietary modifications, such as reducing intake of choline and carnitine-rich foods, can also help. Regular exercise, maintaining a healthy weight, and managing other risk factors (such as high blood pressure and cholesterol) are also important for heart health.

4. Can TMAO levels be tested and monitored?

Yes, TMAO levels can be tested through a blood test. However, it is important to note that TMAO is just one risk factor for heart disease and should be evaluated in conjunction with other risk factors. It is also important to keep in mind that TMAO levels can vary based on recent dietary intake, so a single test may not be completely indicative of overall TMAO levels.

5. Are there any potential risks or drawbacks to following a vegan diet for heart health?

While a well-planned vegan diet can provide numerous health benefits, there are some potential risks and drawbacks to consider. Vegan diets may be lacking in certain nutrients, such as vitamin B12, iron, and omega-3 fatty acids, which could increase the risk of deficiencies if not properly managed. It is important to work with a healthcare professional and ensure a balanced and varied diet to meet all nutrient needs.

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