Headaches. Anxiety. Insomnia. Brain fog. Hives. Nasal congestion. These are just a few of the symptoms of histamine intolerance or mast cell activation syndrome.
Histamine problems are more common in women, and are 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 release histamine and estrogen down-regulates the DAO enzyme that clears 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.
Symptoms of “estrogen dominance” (such as PMS and heavy periods) can actually be symptoms of histamine or “mast cell activation.”
What is histamine?
Histamine is the immune signalling protein that causes allergies and swelling. But it has lots of other jobs. Histamine also 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.
A histamine problem occurs when there is either too histamine being generated or being eaten, or not enough histamine going out.
Reasons for too much “histamine in”
- Mast cell-stimulating foods such as dairy and alcohol. Histamine is a big reason that dairy causes period problems.
- Eating too many histamine-containing foods such as alcohol (especially wine), sauerkraut, and smoked meat.
- Intestinal dysbiosis (wrong gut bacteria) because some species of bacteria make histamine.
- Estrogen excess because estrogen stimulates histamine release.
Reasons for not enough “histamine out”
- A 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?
- cow’s dairy
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 improve your tolerance of histamine foods.
- red wine and champagne
- hard cheese
- smoked or canned fish
- soy sauce
- deli meats
- dried fruit
- dried nuts
- 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 11 of Period Repair Manual.
Supplement vitamin B6 because it upregulates DAO. This is one reason vitamin 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 clearance of estrogen. Read How to lower estrogen.
Consider taking natural progesterone because it up-regulates the DAO enzyme.
👉 Tip: Histamine reduction is a big part of why dairy-free diet, vitamin B6, and natural progesterone work so well for women’s health.
For more information, read The role of histamine and mast cells in PMS and PMDD.