Understanding Mushroom Intolerance
Genetics, dietary changes and everything in between
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, right after pepperoni!
However, this popular food may trigger symptoms in people carrying certain genetic variants. For example, a fascinating study has found that variants of some genes that influence mushroom intolerance influence the intensity of Crohn’s disease symptoms.
The genetics of mushroom intolerance
A study published in the British Journal of Medicine focused on the diet-gene interaction among Crohn’s disease patients. Certain dietary sources were found to intensify the symptoms and aggravate the condition — corn and mushrooms topped this list, which encouraged the researchers to look into a possible genetic factor.
OCTN1 gene
Efforts to study the genetic factors showed a suggestive link between the OCTN1 gene and mushroom intolerance. OCTN1 regulates the transportation of positively charged solutes, most notably, ergothioneine, an amino acid mainly found in mushrooms. Therefore, certain variants of the OCTN1 gene may render improper transportation of ergothioneine, leading to mushroom intolerance.
What’s your genetic variant of the OCTN1 gene? You can upload your 23andMe raw data or your Ancestry DNA raw data to find out!
Genotype and its implication
A change from C to T allele of the OCTN1 gene, a documented risk for Crohn’s disease, influences the tolerance of ergothioneine during Crohn’s disease.
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
Ergothioneine
Ergothioneine is an amino acid that is mainly known for its anti-oxidant properties. It was discovered in 1909 in ergot fungi and hence the name. It is mainly synthesized by certain bacteria and fungi, which is then taken up by plants. While the main source of ergothioneine is mushrooms, other food sources like red beans or oat bran also contain a substantial amount of this amino acid.
More about mushrooms
Mushrooms have always been sought after by nutritionists for their contribution to a healthy diet plan.
Nutrition facts
- 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 fiber
Our Mushroom nutrition facts will not be complete without details about the four 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.
Therapeutic potential of mushrooms
Considering the high anti-oxidant property of mushrooms, there are many therapeutic interventions that use mushrooms as a part of their course. Eating mushrooms every day could rescue the cells from oxidative damage. However, it is best to remain cautious about not overeating mushrooms as it could potentially lead to mushroom intolerance.
The daily required amount of ergothioneine is about 3 milligrams, which is
- 100 grams of button mushrooms a day, or
- 25 grams of shiitake, oyster or maitake mushrooms (4 times more ergothioneine)
In a study that analyzed the effect of mushroom intake in Crohn’s disease patients, it was shown that people with a particular genetic variant had increased transportation of ergothioneine across the plasma membrane. This may have led to an overload of antioxidants in the epithelium and 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.
How is intolerance to mushrooms different from a mushroom allergy?
Mushroom intolerance and mushroom allergy are often confused with each other and used interchangeably.
In mushroom intolerance, the GI’s tolerance to mushroom is compromised due to gene variants or an overload of antioxidants, whereas 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 that people most commonly develop an intolerance for.
As a major boost to the mushroom lovers, The American Chemical Society (2005) stated that mushrooms generally contain a higher concentration of L-ergothioneine than the other two dietary sources of this amino acid — wheat germ and chicken liver.
Further attempts to compare the highest source of L-ergothioneine in the different mushroom types cultivated in the US, showed that shiitake variety contains the most. This could be why shiitake mushroom intolerance is more common.
Sudden mushroom intolerance
There have been reported instances of people developing sudden mushroom intolerance, though they may have never experienced the symptoms earlier.
The type of mushroom consumed, like shiitake, could be partly blamed. Often, the sudden intolerance could also develop from mushroom allergy. The best way to find out is to take up a food intolerance test.
Mushroom intolerance remedy
The only remedy to mushroom intolerance would be to make changes to the diet. The best way to do this would be to completely avoid mushrooms.
While most people take care to avoid mushrooms in their salad when they’re intolerant, what they fail to notice is the presence of ‘hidden’ mushrooms. For example, mushrooms used to make soups, salad dressings, and sauces, mostly go unnoticed. Letting the chef know about your intolerance when you dine out would work well to avoid mushroom ‘contamination’.
As ergothioneine is one major reason for mushroom intolerance, avoiding other sources of ergothioneine like kidney beans, black beans, liver, kidney, and oat bran are generally helpful.
Food intolerance and genetics
The study discussed earlier in the article about ‘mushroom intolerance and Crohn’s disease patients’ is the only risk assessment of its kind. There have been no further studies to identify the risk of mushroom intolerance and symptoms among subjects who do not have Crohn’s disease.
Though mushroom 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. 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.
The overall prevalence of such intolerances has been estimated to be 8% among children and about 5% among adults.
There have been many studies conducted to determine the genetic basis of food intolerance. Family and twin studies have shown a two to ten-fold increase in risk among family members of affected individuals.
The underlying genetic factors that determine food intolerance is being extensively researched with many direct to home genetic testing companies helping in ascertaining risk.
Find out if you have mushroom intolerance
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 (including mushroom intolerance) 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 already 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.
