Mushroom Intolerance: Genetics Of Food Intolerance

A fascinating study has found that mushroom intolerance may be linked by a genetic variant to the intensity of Crohn’s disease symptoms. Mushrooms are loved the world over as they contain flavor enhancers and are a gourmet’s delight. This makes them the most popular choice for pizza topping, after pepperoni ! However, this popular food may trigger symptoms among people with certain genetic variants.

Study on the genetic basis of mushroom intolerance

The study titled “ Mushroom intolerance: a novel diet-gene interaction in Crohn’s disease” focuses on the diet gene interaction among Crohn’s disease patients. The study researchers, who published the article in the British Journal of Medicine, examined the main dietary sources that were found to aggravate Crohn’s disease symptoms. Corn and mushrooms topped this list, which encouraged the researchers to look into a possible genetic factor.

OCTN1- rs1050152

When the scientists delved into the genetic aspect, they found an association between OCTN1 gene and an increased risk for mushroom intolerance. This gene is associated with the transportation of positively charged solutes, in this case, ergothioneine.  

You can upload your 23andme raw data or your Ancestry DNA raw data to check for-   OCTN1- L503F-rs1050152

CC[Advantage] More likely to be ergothioneine tolerant with Crohn's disease
CT[Limitation] More likely to be ergothioneine intolerant with Crohn's disease
TT[Limitation] More likely to be ergothioneine intolerant with Crohn's disease

rs1050152 was previously found to be associated with a risk for Crohn’s disease.

More about ergothioneine

Ergothioneine is an amino acid  with anti-oxidant properties discovered in 1909 in ergot fungi. This amino acid is synthesized by certain bacteria and fungi, which is then taken up by plants. The main source of ergothioneine are mushrooms, while there are other food sources as well , like red beans or oat bran.


Some nutrition facts about mushroom.

Mushrooms have always been sought after by nutritionists for their contribution to a healthy diet plan.

  • They lack cholesterol
  • They are gluten free
  • They are low in fats, sodium and sugars
  • They are low in calories
  • They are known for their medicinal properties
  • They are good sources of vitamin B
  • They are rich in fibre

Our Mushroom nutrition facts will not be complete without details about the 4 vital nutrients that they include- ergothioneine,  selenium, glutathione and vitamin D. These nutrients are believed to have very high anti-oxidant property, with research studies showing that they can be used to lower risk for diseases such as Cancer, Alzheimer’s disease and Parkinson’s disease.

Considering the high anti-oxidant property of mushrooms, there are many alternate therapy treatment measures which use mushrooms as a part of their medicines. Eating mushrooms everyday could increase antioxidant levels.

The required amount of ergothioneine  is about three milligrams per day, which is

  • 100 grams of button mushrooms a day,
  • or 25 grams of shiitake, oyster or maiitake mushrooms, as they have nearly 4 times more amount of ergothioneine

Though the anti-oxidant property is beneficial to control oxidation, in the study on the effect of mushroom intake among Crohn’s disease patients, people with the genetic variant had increased transportation of ergothioneine across the plasma membrane. This may have lead to an overload of antioxidants, according to the study, in the epithelium and in the red blood cells, resulting in an immune reaction and GI intolerance to mushrooms.  


Symptoms of mushroom intolerance.

Abdominal discomfort and severe cramping are the main mushroom intolerance symptoms, though the study discusses a flare up of Crohn’s disease among people with this type of food intolerance.


Difference between mushroom intolerance and mushroom allergy

Mushroom intolerance is different from mushroom allergy. In mushroom allergy, mushroom antigens could trigger symptoms, even if they have not been ingested. The symptoms of mushroom allergy can range from vomiting, nausea, shock and, in severe cases, even anaphylaxis.

People at high risk for mushroom allergy include:

  • Individuals handling mushrooms in packaging industries
  • Individuals who consume mushrooms without sufficient cleaning
  • Individuals who inhale the fungal spores

Shiitake mushroom intolerance

Shiitake is a type of mushroom and shiitake mushroom intolerance is one of the most common forms of mushroom intolerance. In a major boost to shiitake lovers, The American chemical society in 2005 stated that mushroom contained the highest concentrations of L-ergothioneine, higher that either of the two dietary sources, wheat germ and chicken liver, which were  previously believed to contain the most. When compared with the other types of mushrooms cultivated in the US, the shiitake variety contained the highest amount of L-ergothioneine, which would mean that shiitake mushroom intolerance is probably more likely to occur.


Sudden mushroom intolerance

There have been reported instances of people developing sudden mushroom intolerance, though they may have never experienced the symptoms earlier. This could either be due to the type of mushroom consumed, like shiitake mushroom intolerance or it could be due to mushroom allergy. The best way to find out is to take up a food intolerance test.


Mushroom Intolerance remedy

The best and the only way to avoid mushroom intolerance is to completely remove mushrooms from the diet. Though most people who realise the significance of mushroom intolerance would avoid mushrooms from their salads, most people are unaware of ‘hidden’ mushroom presence in food. Many soups contain mushroom while there are salad dressings and sauces that also contain mushrooms. Letting the chef know about your intolerance when you dine out would work well to avoid mushroom ‘contamination’.

The available study on the genetic basis of mushroom intolerance identified ergothioneine as the ‘component’ that lead to the intolerance. There, other ergothioneine rich foods to avoid or restrict would be, kidney beans, black beans, liver , kidney and oat bran.


How To Find Out If You Have Mushroom Intolerance

The study published in the British Medical Journal was conducted on Crohn’s disease patients. There have been no further studies conducted to identify the risk of mushroom intolerance and subsequent symptoms among subjects who did not have Crohn’s disease.

Though this type of food intolerance is limited by the extent of genetic association, there are other food intolerances like gluten sensitivity, histamine intolerance, lactose intolerance and caffeine sensitivity with strong genetic determinants.

Food intolerance is an adverse reaction to food ingested, like lactose intolerance or gluten sensitivity. The number of food allergens and type are diverse, ranging from peanuts to eggs to shrimp and more. The overall prevalence of such intolerances has been estimated to be 8% among children and about 5% among Adults. Though there is no medication that can be used to prevent food intolerance, identifying the risk for these conditions will help in avoiding their consumption.

There have been many studies conducted to determine the genetic basis of food intolerance, and family and twin studies have shown that there was two to ten-fold increase in risk among family members of affected individuals, with an incidence ranging from 15 to 80%.

The underlying genetic factors that determine food intolerance is being extensively researched with many direct to home genetic testing companies helping in ascertaining risk.

Among the various genetic testing companies, 23andme and Ancestry DNA provide a wide number of genetic markers (650,000). This information is present in the raw data file provided by these ancestry testing companies and this information can be used to obtain vital information about food intolerances as well as many other allergic conditions that have a genetic basis.

If you have not availed a genetic test from 23andme, click here to do so.

If you do have your 23andme raw data or Ancestry DNA raw data, you can upload it onto Xcode. Life to receive information about your risk for different types of allergy. Please click here to order our reports.



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