Spring is in full force here! Time to dust off the lawnmower. As that smell of fresh-cut grass fills the air, many people also get watery eyes, runny noses, and itching everything.
Speaking of smelling the grass… Did you know that some people can’t smell the odor of fresh-cut grass? There is actually a genetic variant (not covered by 23andMe data) that prevents some people from knowing that wonderful summertime smell.
Grass Allergies and Genetics:
Allergies are usually due to a mix of genetic susceptibility and being exposed to certain triggering molecules. Several different gene variants have ties to an increased risk of grass pollen allergies.
A study found that in people with grass pollen allergies there was an upregulation of MC1R in their noses.[ref] If that gene sounds familiar, it is the same gene that codes for the melanin receptor which causes red hair.
Human leukocyte antigens (HLA) are part of our immune system and help the body recognize foreign invaders. People have many different variants of these genes, giving rise to protection against different pathogens. Different HLA types lead to an increased ability to fight off diseases and also lead to increased susceptibility to autoimmune diseases and allergies.
Check your genetic data for rs7775228 (23andMe v4, v5):
- C/C: more likely to be allergic to grass pollen (OR=1.33)[ref]
- C/T: more likely to be allergic to grass pollen
- T/T: typical (most common genotype)
Members: Your genotype for rs7775228 is —.
Filaggrin, a protein encoded by the FLG gene, increases the epithelial integrity. Variants that decrease filaggrin have ties to different types of allergies.
Check your genetic data for rs61816761 R501X (23andMe v4, v5):
- A/A: (rare) more likely to be allergic to grass pollen[ref]
- A/G: more likely to be allergic to grass pollen
- G/G: typical (most common genotype)
Members: Your genotype for rs61816761 is —.
Interleukin 2 (IL2) is involved in the body’s immune system response to foreign invaders. It is a cytokine produced by Th1 cells when stimulated by, in this case, an allergen.
Check your genetic data for rs2069762 -330T/G (23andMe v4, v5):
- A/A: typical (most common genotype)
- A/G: normal risk of grass allergy
- G/G: 2.6x increased risk of grass allergy[ref]
Members: Your genotype for rs2069762 is —.
Interleukin 33 is involved in the body’s immune system response, also. IL-33 drives the production of Th2 cytokines, acting on mast cells (among others). It is thought to be responsible for itching sensations from allergies.[ref]
Check your genetic data for rs928413 (23andMe v4, v5):
- A/A: typical
- A/G: increased risk of hay fever, allergy
- G/G: increased risk of hay fever[ref]
Members: Your genotype for rs928413 is —.
A study on children with seasonal pollen allergies compared the effects of 1,000 IU of Vitamin D daily vs. placebo.[ref] The study found that the vitamin D group had reduced allergy symptoms compared to the placebo group. Another study looked at vitamin D combined with Lactobacillus rhamnosus GG (probiotic) on children’s allergies and found the combo effective.[ref]
Nasal rinsing has been shown to be effective for grass pollen allergies.[ref] The easiest way to nasal rinse is by using a sinus rinse kit or with a neti pot.
Spirulina, in studies, seems to reduce the symptoms of allergic rhinitis.[ref][ref] You should be able to find spirulina in any health food store, or you can get it online. Look for an organic version.
Bifidobacterium lactis reduced grass pollen reactions (taken for 8 weeks).[ref]
If you normally take antihistamines for pollen allergies, this study suggests that taking the antihistamines for three days before the exposure prevented the histamine 1 (H1) receptors from increasing expression in the nose. In an allergic response, your body releases histamine as a signaling molecule, and then the receptors for histamine cause the reaction to occur. H1 receptors are the ones involved in your typical seasonal allergy reaction with a runny nose and itchy, watery eyes. So the study showed that without the increase in histamine receptors, there were few allergy type symptoms. The antihistamine prevented the body from upregulating the H1 receptors.[ref]
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