Is Shrimp Bad for Cholesterol and Heart Disease?

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Might asymptomatic food sensitivities to gluten, milk, peanuts, eggs, or shrimp increase the risk of premature death for those who eat these foods?

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

When people were randomized to consume shellfish or the same weight of protein of meat, cheese, and eggs, surprisingly shrimp did not lower their LDL cholesterol––perhaps because shrimp is so high in dietary cholesterol. Shrimp is exceedingly low in saturated fat, like 30 times less than other meat. But it has about twice as much cholesterol, which dietary guidelines recommend we reduce in our diet to as low as possible. If people are given the same amount of cholesterol in the form of shrimp or eggs, they get about the same rise in LDL cholesterol, which alone could increase our lifetime risk of heart disease by about 15%. But there are a lot more people eating two eggs a day than like 11 ounces (310 g) of shrimp a day. And eating wild-caught cold-water prawns, a different species of shrimp, doesn’t appear to budge LDL cholesterol much at all. Unfortunately, about one in three shrimp in the grocery store is mislabeled, so it may be hard to pick and choose.

There is another way meat may contribute to heart disease risk. In certain areas of the United States and around the world, getting bitten by certain types of ticks can make you allergic to meat. In some parts of the U.S. where the lone star tick is endemic, as many as 20% of people have allergy-type antibodies against meat in their bloodstream. But the prevalence of clinically appreciated allergic symptoms is thought to be at least 10-fold less. So, they’re sensitized to meat, but when they eat it, they don’t exhibit any symptoms. And because of that, they continue to eat meat. But what if that’s causing inflammation inside their bodies, even if they don’t feel it? And most concerningly, what if it’s causing more inflammation in their artery walls? Indeed, there were significantly greater amounts of atherosclerotic plaque in the individuals who had detectable levels of the anti-meat allergy antibodies in their system. So, people who consume mammalian meat appear to have this chronic inflammation in the walls of their coronary arteries that relates to this interaction between this alpha-gal component of meat and their anti-alpha-gal antibodies, if they’ve been bitten by a tick.

Those having a heart attack had about a whopping 13 times higher likelihood to having those antibodies, providing strong supportive evidence for a clinically important effect of alpha-gal sensitization on the development of coronary heart disease, our leading cause of death, and acute myocardial infarction, or heart attack. Okay, but wait a second. If having an asymptomatic food allergy can so inflame our arteries, what about other food allergies?

An allergy to shrimp is actually the most common food allergy in the United States, affecting up to 1 in 50 Americans. But those are the people who experience symptoms. Might a shrimp allergy actually be affecting more? People with symptomatic seafood allergies tend to know they are allergic, and know to just stay away from shrimp. But some people with shrimp allergies react differently. Some have classic allergy symptoms like breaking out in hives, swelling, and difficulty breathing, but others develop symptoms that manifest hours later—gastrointestinal symptoms like nausea, abdominal cramps, diarrhea, and vomiting. So, some shrimp-sensitive patients just have this kind of gastrointestinal upset. But what about people who are sensitized to shrimp, and they don’t even know it because they don’t exhibit any symptoms?

In individuals without symptomatic food allergy, having allergy antibodies in their blood targeting some food was considered clinically irrelevant. But that was before those tick-induced meat sensitization studies came out. So, researchers looked to see if having allergy antibodies against foods was associated with cardiovascular mortality, and, indeed, that’s just what they found. From blood tests, it appears about one in 25 people is allergic to milk, whether they know it or not. And in these two large studies, those who had the milk sensitivity had between two and nearly four times the risk of dying from cardiovascular disease, but the worst appeared to be shrimp. Six percent of Americans, about one in 17, have anti-shrimp antibodies in their blood, whether they know it or not, and those who do are 3.7 times more likely to die of cardiovascular disease––but only if they eat shrimp. Having anti-shrimp antibodies doesn’t matter if you don’t eat shrimp.

What about having a milk, peanut, or egg sensitivity, but not eating those foods? There were too few people not eating those foods to actually calculate it, but enough people don’t eat shrimp that researchers could see that having anti-shrimp antibodies only mattered if you kept eating shrimp. The thought is that chronic oral exposure to foods we have hidden allergy antibodies for can lead to chronic inflammation that can manifest in our arteries. This definitely challenges the current thinking that these kinds of food sensitivities without overt allergy is benign.

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

When people were randomized to consume shellfish or the same weight of protein of meat, cheese, and eggs, surprisingly shrimp did not lower their LDL cholesterol––perhaps because shrimp is so high in dietary cholesterol. Shrimp is exceedingly low in saturated fat, like 30 times less than other meat. But it has about twice as much cholesterol, which dietary guidelines recommend we reduce in our diet to as low as possible. If people are given the same amount of cholesterol in the form of shrimp or eggs, they get about the same rise in LDL cholesterol, which alone could increase our lifetime risk of heart disease by about 15%. But there are a lot more people eating two eggs a day than like 11 ounces (310 g) of shrimp a day. And eating wild-caught cold-water prawns, a different species of shrimp, doesn’t appear to budge LDL cholesterol much at all. Unfortunately, about one in three shrimp in the grocery store is mislabeled, so it may be hard to pick and choose.

There is another way meat may contribute to heart disease risk. In certain areas of the United States and around the world, getting bitten by certain types of ticks can make you allergic to meat. In some parts of the U.S. where the lone star tick is endemic, as many as 20% of people have allergy-type antibodies against meat in their bloodstream. But the prevalence of clinically appreciated allergic symptoms is thought to be at least 10-fold less. So, they’re sensitized to meat, but when they eat it, they don’t exhibit any symptoms. And because of that, they continue to eat meat. But what if that’s causing inflammation inside their bodies, even if they don’t feel it? And most concerningly, what if it’s causing more inflammation in their artery walls? Indeed, there were significantly greater amounts of atherosclerotic plaque in the individuals who had detectable levels of the anti-meat allergy antibodies in their system. So, people who consume mammalian meat appear to have this chronic inflammation in the walls of their coronary arteries that relates to this interaction between this alpha-gal component of meat and their anti-alpha-gal antibodies, if they’ve been bitten by a tick.

Those having a heart attack had about a whopping 13 times higher likelihood to having those antibodies, providing strong supportive evidence for a clinically important effect of alpha-gal sensitization on the development of coronary heart disease, our leading cause of death, and acute myocardial infarction, or heart attack. Okay, but wait a second. If having an asymptomatic food allergy can so inflame our arteries, what about other food allergies?

An allergy to shrimp is actually the most common food allergy in the United States, affecting up to 1 in 50 Americans. But those are the people who experience symptoms. Might a shrimp allergy actually be affecting more? People with symptomatic seafood allergies tend to know they are allergic, and know to just stay away from shrimp. But some people with shrimp allergies react differently. Some have classic allergy symptoms like breaking out in hives, swelling, and difficulty breathing, but others develop symptoms that manifest hours later—gastrointestinal symptoms like nausea, abdominal cramps, diarrhea, and vomiting. So, some shrimp-sensitive patients just have this kind of gastrointestinal upset. But what about people who are sensitized to shrimp, and they don’t even know it because they don’t exhibit any symptoms?

In individuals without symptomatic food allergy, having allergy antibodies in their blood targeting some food was considered clinically irrelevant. But that was before those tick-induced meat sensitization studies came out. So, researchers looked to see if having allergy antibodies against foods was associated with cardiovascular mortality, and, indeed, that’s just what they found. From blood tests, it appears about one in 25 people is allergic to milk, whether they know it or not. And in these two large studies, those who had the milk sensitivity had between two and nearly four times the risk of dying from cardiovascular disease, but the worst appeared to be shrimp. Six percent of Americans, about one in 17, have anti-shrimp antibodies in their blood, whether they know it or not, and those who do are 3.7 times more likely to die of cardiovascular disease––but only if they eat shrimp. Having anti-shrimp antibodies doesn’t matter if you don’t eat shrimp.

What about having a milk, peanut, or egg sensitivity, but not eating those foods? There were too few people not eating those foods to actually calculate it, but enough people don’t eat shrimp that researchers could see that having anti-shrimp antibodies only mattered if you kept eating shrimp. The thought is that chronic oral exposure to foods we have hidden allergy antibodies for can lead to chronic inflammation that can manifest in our arteries. This definitely challenges the current thinking that these kinds of food sensitivities without overt allergy is benign.

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Doctor's Note

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