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Paleo and Menstrual Cramps

Cramps: SOS

There are two kinds of women in the world: women who go through an entire bottle of Midol every month, and women who don’t.

If you’re in the first group, you aren’t alone: 20% of women in the United States have cramps bad enough to interfere with their normal activities (work or school). But on the other hand, just because something is common in the context of the modern diet and lifestyle doesn’t mean it’s an inevitable part of human life. The evidence we have from hunter-gatherer women, for example, suggests that their periods are much lighter and rarely painful at all – is there something to learn here? Could diet actually play a role in reducing menstrual discomfort? As it turns out, it just might.

What Are Menstrual Cramps?

There are two kinds of menstrual cramps: primary and secondary.

Secondary menstrual cramps are caused by an underlying problem deeper than the cramps themselves. Certain types of uterine tumors, endometriosis, or fibroids can cause extremely painful cramping, for example. If you have one of these conditions, then the best treatment will come from your doctor, not from the internet. But fortunately, secondary cramps are rare. Primary menstrual cramps (also called primary dysmenorrhea) are the ones almost everyone has, and they don’t indicate anything serious; they just hurt.

So what’s behind primary menstrual cramps, and why do some women get them while others don’t? On a purely symptomatic level, menstrual cramps are really just muscle spasms like any other kind of cramp that you might get from going too hard in the gym. But that doesn’t explain where they come from, since you’re obviously not deadlifting anything with your uterus.

The origin of menstrual pain is complicated. In some cases, it’s genetic; it’s also related to age (younger women tend to have it worse), early puberty, and heavy menstrual flow. But behind all this seems to be an underlying inflammatory problem, caused by a spiteful group of hormone-like chemical compounds called prostaglandins. Higher levels of prostaglandins trigger the muscles surrounding the uterus to contract, causing painful cramps and other symptoms.

In other words, when we’re talking about menstrual cramps, the real culprit is inflammation – and if there’s one problem that Paleo knows how to fight, it’s inflammation.

Diet and Menstrual Cramps: Micronutrients

Several different dietary intervention strategies have shown impressive effectiveness in treating menstrual cramps. Some of these might be things you’re automatically getting plenty of on Paleo anyway (possibly the reason why just switching to Paleo improves some women’s cramps); others might be potential nutrients to supplement with, or to take special care to eat around your period.

Thiamine (Vitamin B1)

According to this systematic review, thiamine (Vitamin B1) may be effective in reducing menstrual cramps. 1 group of young women with painful cramps was treated with 100mg of thiamine every day for 90 days, while the others got a placebo. In the thiamine group, 51% reported a pain-free period, while in the placebo group, none of the women had any improvement.

In another study that wasn’t quite as well-designed, the results were even more dramatic. After 100mg of B1 eliminated symptoms in 87% of the treatment group and reduced the pain in an additional 8%, with only 5% showing no change.

One thing to bear in mind with both of these studies is that 100mg of thiamine is truly a megadose: the RDA for most adults is 1-1.5mg. So if you want to get that much, you’re going to have to take a supplement (unless you feel like eating 44 pounds of tuna every day). There isn’t any documented danger of megadosing, though, so it’s a pretty safe painkiller to try. If you’re interested in experimenting with a more moderate dosage first, foods high in Vitamin B1 include pork, asparagus, mushrooms, spinach, tuna, and Brussels sprouts.

Vitamin E

For Vitamin E, a randomized, double-blind, placebo-controlled study found that Vitamin E supplements were effective in reducing both the duration and the severity of cramps. The supplement group got 200 IU (133mg) of Vitamin E supplements starting two days before their period was due, and kept taking it until they’d been menstruating for 3 days. On average, the pain severity was significantly lower in the Vitamin E group, and the duration of pain also reduced dramatically. After two months, girls in the Vitamin E group experienced pain for 4.2 hours on average, compared with 15 hours in the control group. And after four months, the Vitamin E group was only hurting for 1.6 hours, compared with 17 hours in the control group.

Like the B1 supplements, this is pretty far above what you could reasonably expect to get from food (for comparison, the RDA is 20mg/day). So if you’re looking to re-create the study conditions, you’ll need a supplement. But if you’d like to see if just eating Vitamin E-rich foods can help, you could try avocado, almonds, hazelnuts, spinach, or broccoli.


Magnesium doesn’t have as much evidence behind it, but it’s still interesting. A small study in Germany (only 21 patients) found that magnesium taken a day before the menstrual cycle began helped with pain on the second and third day, suggesting that it’s better to get a couple days’ lead time instead of just starting the magnesium when you start bleeding.  Another study confirmed this: 4.5mg of magnesium starting a week before the onset of bleeding helped reduce pain on the first day of the women’s periods, with the benefits getting better and better over the 6 months of the study.

This really shouldn’t be a surprise to anyone, considering that magnesium is a natural muscle relaxer, and one of the best ways to treat muscle cramps from any source. And best of all, the dose of magnesium used in the second study was relatively tiny (for comparison, the RDA is 400mg), so it’s extremely easy to get from foods. Magnesium-rich foods include many types of fish (mackerel, salmon, and halibut), spinach, avocado, white potatoes, and most nuts and seeds.

Female anatomyDiet and Menstrual Cramps: Fats

On top of the question of micronutrients is the issue of fat quality. Inflammation has a lot to do with fat, and Omega-6 fatty acids are necessary precursors for prostaglandins (the chemical compounds responsible for the painful contractions of menstrual cramps). So it makes sense that changing the fatty acid composition of your diet might help.

If you’ve been eating Paleo for any length of time, you can probably tell where this is going: more Omega-3s, fewer Omega-6s, and a better ratio between the two (if you’re new to this, check out this article for a brief primer on what this means). So what’s the evidence for this?

Starting with the epidemiological research (which does not prove causation but is interesting anyway), in this study, a low intake of Omega-3 fats and Vitamin B12, as well as a poor Omega-3:Omega-6 ratio were all correlated with painful periods in Danish women.

Then there are some intervention trials showing that fish oil might have an effect. One small study (only 42 women) found an improvement, but this study gave the women both fish oil and Vitamin E, so it’s hard to separate the effects of one from the other. This study was also in girls who self-reported a low consumption of fish, so it’s not clear that the effects would hold for people who eat fish regularly (and thus are unlikely to be deficient in O3s).

In this study, two groups of women took either an Omega-3 supplement for 3 months or a placebo. After 3 months on the Omega-3 supplement, Group 1 needed an average of 4.3 ibuprofen tablets per cycle, compared to 5.3 on the placebo. The results from Group 2 were even better: after 3 months on the supplement, they needed 3.2 ibuprofen tablets, compared to 6 on the placebo. This study found that fish oil from anchovies also reduced both pain scores and painkiller use among 36 young women (age 18-22).

The take-home: the evidence we have suggests that optimal Omega-3 to Omega-6 ratios might help reduce menstrual cramps. It’s not definitive proof that you should take a fish oil supplement (since on Paleo, you’re likely to be getting plenty of Omega-3s from food alone), but it’s certainly an argument for eating some fish on a regular basis!

A brief footnote on the topic of fat: you might have also read that a low-fat vegetarian diet will help with cramps, probably based on evidence from this study. But if you actually read the study, you’ll notice that the low-fat vegetarian diet was compared to the subjects’ “customary diet,” and considering that these were American women that “customary diet” was almost certainly full of junk. So this is pretty convincing if you want to argue that “making an effort to eat healthy foods is better than making no effort at all,” but it doesn’t prove anything about a low-fat vegetarian diet compared to Paleo (or any other health-focused diet).

Diet and Menstrual Cramps: Hormones

A final factor that menstrual cramps is, of course, hormones. Estrogen dominance (too much estrogen relative to other hormones like progesterone) is definitely a factor in menstrual cramping and pain. It’s highly likely that the amount of hormone-disrupting environmental toxins in the modern environment have something to do with this – but this is next to impossible to measure, because everyone is exposed to these toxins, so how could you possibly get a control group? In terms of diet specifically, it’s also very tricky to make a call, because there simply isn’t much research to go on.

The most obvious place to look is soy, which contains phytoestrogens (estrogen-mimicking chemicals) that can have dangerous effects on other aspects of reproductive health. But in this study, neither soy nor fat intake was correlated with menstrual cramping in Japanese women. The only other literature in PubMed that’s even relevant is this set of three case reports from women whose menstrual cramps improved after they stopped eating soy, but this proves nothing by itself, since case reports are some of the lowest-quality evidence around.

The upshot is that, while soy may play a role in menstrual pain, there’s nothing around to definitively prove that it does. Of course, on Paleo this isn’t so much of an issue since you shouldn’t be eating soy anyway, but it’s still useful information to have for reference.


Menstrual cramps aren’t just about diet. They’re also related to lifestyle: exercise, for example, helps a lot, while stress makes everything worse. Environmental toxins probably aren’t doing anyone any favors, and genetics always have to have their say. So there is no specific diet that can magically cure the discomfort of a painful period. But fortunately, Paleo is a lifestyle and not just a diet – so if you’re eating Paleo, you’re probably also working on your exercise, stress levels, and toxin exposure. And diet, plus some well-placed supplements if you need them, can certainly help.