Seed cycling has been touted as helping to regulate menstrual cycles. One is supposed to take a combination of flax and pumpkin seeds (1-2 tablespoons each) during the first half of the cycle (from when your period starts until you ovulate, the “follicular phase”) and then sesame and sunflower seeds during the second half (after ovulation until your period starts again, the “luteal phase”). And if you have no period, you’re told to follow the cycle of the moon, taking the flax/pumpkin seeds from full moon to new moon, and the sesame/sunflower combo from new moon to full moon.
quick summary of evidence-based recommendations:
I find no support in the medical literature for the idea of switching seeds based on cycle phase, in fact, every study uses one (or two) seeds consistently for weeks to months at a time before benefits are seen. The highest quality evidence suggests flax seed for increasing luteal phase length, and sesame seeds for women with PCOS (increases sex homone binding globulin, which is typically low in women with PCOS). I recommend using these seeds consistently, not switching back and forth. If you do not currently have menstrual cycles, the strongest evidence suggests benefits of daily flax seed consumption.
Info on seed cycling
In some places discussions of seed cycling seems reasonable – like this article at Natural Health Perspectives, or this one at Herbal Academy where they discuss the lignans from the seed hulls as helping to modulate hormones (these are phytoestrogens that can affect your hormone levels) and fatty acids in the seed body that provide omega fatty acids that provide the building blocks for making the hormones estradiol and progesterone. And then there seems to be a protocol making the rounds where the explanation is that during the follicular phase that you use flax and pumpkin seeds “to block excess estrogen” and then sesame and sunflower seeds during the second half of the cycle “to help block excess estrogen”. Um, what? that makes no sense. There are times in your cycle when you need and want estrogen! (like when the follicle is growing during the follicular phase).
In line with my ongoing series examining supplement use and recovery of missing periods (hypothalamic amenorrhea), I wanted to examine the scientific underpinnings of this idea. Is there any real basis to switching seeds during the middle of the cycle (especially when the explanation of how the seeds are affecting hormones seems to be the same in both phases…)?
what is the evidence for seed cycling?
If you look in the medical literature (pubmed or google scholar searches), there are no published studies comparing seed cycling with any kind of control, or looking at alterations in hormone levels when using the variation of seeds. So the only evidence we have is inference from other studies, and anecdotes.
There is some evidence for the individual seeds. I covered flax seed in a recent post, In summary, flax seed has been shown in clinical studies to be associated with more ovulatory cycles, longer luteal phase, lower stress hormones and perception of stress. I do think that having 10g (ground) flax seed per day is a worthwhile addition to your daily fare, based not only on the cycle related benefits I just listed, but also overall health benefits.
So now let’s look at the other seeds. In seed cycling, flax seed is supposed to be paired with pumpkin seed. Continue reading