Headaches. Anxiety. Insomnia. Brain fog. Hives. Nasal congestion. These are just a few of the symptoms of histamine intolerance.
Histamine intolerance is more common in women, and is often worse at ovulation and just before the period. Why? Because that’s when estrogen is high compared to progesterone, and estrogen increases histamine.
Estrogen stimulates mast cells to make more histamine and estrogen down-regulates the DAO enzyme that you need to clear histamine. At the same time, histamine stimulates the ovaries to make more estrogen. The net result is a vicious cycle of:
estrogen → histamine → estrogen → histamine.
For many women, symptoms of “estrogen dominance” such as PMS, period pain, and heavy periods improve by taking steps to reduce histamine.
What is histamine intolerance?
You best know histamine as the immune signaling protein that causes allergies and swelling. But histamine has lots of other jobs. It regulates stomach acid, stimulates the brain, and plays a key role in ovulation and female reproduction.
Did you know? Histamine boosts libido, which is why estrogen increases libido and antihistamines decrease it.
Normally, your body regulates histamine by making it, and then by clearing it with the enzymes histamine N-methyltransferase (HNMT) and diamine oxidase (DAO). It’s a fine balance between “histamine in” and “histamine out”.
Did you know? The placenta makes a huge amount of DAO, which is why histamine intolerance and food sensitivities often improve during pregnancy.
Histamine intolerance occurs when there is either too much coming in, or not enough going out—or both!
⚠️ Warning: “Histamine intolerance” is not a recognized medical diagnosis, so your doctor may not want to hear about it.
Reasons for too much “histamine in”
- Food sensitivities such as gluten and casein (dairy) because they stimulate histamine release. (This is one reason dairy causes so many period problems.)
- Too many high-histamine foods such as red wine, sauerkraut, and cured meat.
- Intestinal dysbiosis (wrong gut bacteria) because some species of bacteria make histamine.
- Estrogen excess because estrogen stimulates histamine.
Reasons for not enough “histamine out”
- Genetic variant of the histamine-clearing enzymes HNMT and DAO.
- SIBO (small intestinal bacterial overgrowth) because it impairs DAO activity.
- Vitamin B6 deficiency because vitamin B6 is an essential cofactor of DAO.
- Estrogen excess because it down-regulates DAO.
- Progesterone deficiency because progesterone is needed to up-regulate DAO. That’s why you have more DAO (and less histamine) early in the luteal phase when progesterone is high. (Better histamine clearance is just one of many ways that progesterone feels good.)
- Hormonal birth control because it causes estrogen excess and progesterone deficiency.
What’s the solution?
Reduce histamine-containing foods. This is the fastest and simplest way to feel better, but it can become restrictive and difficult in the long term. If you address underlying gut issues, you should find that you can better tolerate histamine foods.
High histamine foods:
Red wine and champagne
Cured meat and fish
Bone broth and fish stock
Vinegar and fermented foods such as sauerkraut
Improve gut health. This usually means identifying and correcting dysbiosis and small intestinal bacterial overgrowth (SIBO). I discuss SIBO in Chapter 10 of my book Period Repair Manual.
Supplement vitamin B6 because it upregulates DAO. This is one of the reasons that B6 is so incredibly helpful for PMS. (B6 also boosts the calming neurotransmitter GABA.) Food sources of vitamin B6 include meat, chicken, and sunflower seeds.
Promote the healthy detoxification of estrogen. See The Ups and Downs of Estrogen: Estrogen Excess.
Consider taking natural progesterone because it up-regulates DAO. For more information, see the 7 Superpowers of Progesterone.
⚠️ Tip: Histamine reduction is a big part of why vitamin B6 and natural progesterone work so well for women’s health.
What is your experience with histamine intolerance? Please leave a comment.