Some people thrive on spicy foods — eating the ghost pepper salsa or ordering the ‘nuclear’ hot wings. Are these people just tougher? stronger? superior? Or are they the genetic oddities? Personally, I say that there is no shame in being a spicy food wimp!
Capsaicin is the component of chili peppers that makes them taste hot. It binds to a specific receptor called the TRPV1 receptor, which gives us the perception of heat and pain from spicy foods.
Interestingly, birds don’t respond to capsaicin, so the hot pepper seeds don’t bother them, but most mammals avoid capsaicin due to the pain. This is an advantage for plants since seeds tend to pass on through birds, distributing the plants far and wide. Whereas mammals are more likely to destroy the seeds with their teeth not passing them on. [ref]
So why are some people less bothered by spicy foods? Repeated exposure to capsaicin turns down the TRPV1 receptor.
Who on earth would want to eat enough spicy food to have repeated exposure? People who have variants of the TRPV1 receptors that cause them not to feel as much pain.
TRPV1 stands for transient receptor potential vanilloid 1. This is the gene that codes for the receptor that is activated by capsaicin. This receptor is also involved in body temperature regulation.
TRPV1 is activated by:
The TRPV1 receptors are mainly found in the peripheral nervous system in the nociceptive (pain-sensing) neurons. [ref]
Capsaicin cause you to feel heat and pain through activating the pain receptors in the peripheral nervous system. But repeated exposure to capsaicin will decrease the TRPV1 receptor activity, causing you to be less sensitive to pain. This is why capsaicin can be used to decreasing the pain of arthritis.
Beyond just signaling pain, the TRPV1 receptor plays other important roles within the body. It is important in the cardiovascular system and in insulin release. [ref][ref] TRPV1 activation increases insulin sensitivity and is therefore involved in energy expenditure and diabetes.[ref]
Genetic variants that decrease the amount of TRPV1 should give a greater tolerance to spicy foods. These variants are also linked to less sensitivity to tasting salt and a decreased risk of diabetes.
Check your genetic data for rs8065080 (23andMe v5; AncestryDNA):
Check your genetic data for rs222741 (23andMe v4; AncestryDNA):
Check your genetic data for rs222747 (AncestryDNA only):
*given here in the plus orientation to match AncestryDNA orientation.
Check your genetic data for rs161364 (23andMe v4 only):
Check your genetic data for rs224534 (23andMe v4, v5; AncestryDNA):
What can you do if you are a spicy foods wimp?
In mice, capsaicin reduces obesity from a high-fat diet. It also helps with insulin sensitivity.[ref][ref][ref] The human studies aren’t all that impressive for weight loss or weight loss maintenance, but there may be minor benefits for some.[ref]
If you have ever started dripping with sweat after eating something spicy, there is a name for this — gustatory sweating – and it is caused by the thermoregulation by TRPV1. [ref] This thermoregulation is thought to be why eating spicy foods in a hot climate ends up cooling you off (theoretically). [ref]
Capsaicin creams have been shown to be effective for arthritis pain, shingles, and muscle pain. They work by repeated exposure to capsaicin causing a decrease in TRPV1. [ref]
Capsinoids are similar to capsaicin but without the hotness. Capsinoids are found in a type of chili pepper known as CH-19 Sweet. They give the metabolic benefits of capsaicin without the spice. [ref]
Cannabidiol (CBD oil) is a part of the cannabis plant that doesn’t get you high. It binds to the TRPV1 receptor as an agonist, and this is at least part of why it is effective for pain for some people.[ref] In theory, taking CBD oil before eating spicy foods should decrease the pain. There aren’t any studies on this, though, that I could find.