Menstrual cycles don’t have to remain a mystery. Here’s what happens – to your body, your hormones, and how you feel – and how nutrition can help, by Hatty Willmoth.

Menstrual cycles are about more than just periods. Over the course of a single month, rises and falls in sex hormones alter how we feel, how we think, and our bodies.

Beyond the bleed, many of us know precious little about the details.

Yet experts such as Marilyn Glenville – a specialist in nutritional health for women – say that understanding our cycles, listening to our bodies, and eating the right nutrients can help improve the whole process.

Four phases of the menstrual cycle

A menstrual cycle is a continual rhythm of hormonal fluctuations and physical changes so there are plenty of ways to divide it up.

And each slightly different splice of the cycle comes with its own jargon: menses, follicular, proliferative, ovulatory, secretory, luteal… The list goes on.

But it is becoming increasingly common to divide the cycle into four ‘seasons’.

Winter refers to the period; then comes spring; summer is ovulation; and autumn is the pre-menstrual phase.

It’s important to note that every cycle is different. The average length is 28 days, and this is a useful framework for describing what happens throughout a normal cycle, but a normal cycle can last anywhere between 21 and 40 days.

The same goes for symptoms and the way each phase makes us feel. There are trends and patterns, but what’s normal for you may not be normal for the next person.

Winter: the period

The menstrual cycle begins on the first day of bleeding. This shedding of the endometrium – the lining of the uterus: blood, mucus and tissue – should last between three and seven days.

It’s prompted by a stark drop in two key sex hormones: oestrogen and progesterone.

And it can come with various symptoms, such as:

  • Cramps
  • Sore, swollen or tender breasts
  • Bloating and disrupted digestion
  • Mood swings and irritability
  • Headaches or migraines
  • Tiredness
  • Lower back pain
  • Inflammation
  • Oily skin and scalp, and acne

Spring: the follicular phase

Once the winter period is over, inner spring begins.

Alternative labels include ‘follicular’, ‘pre-ovulatory’ or ‘proliferative’ phase, but these can sometimes refer to the period too.

At this stage, low progesterone has triggered the release of follicle stimulating hormone (FSH), which – as the name suggests – stimulates the growth of between five and 20 follicles: small sacs in the ovaries that contain immature eggs.

Eventually, one follicle begins to dominate; it continues to mature, while the rest are resorbed into the body.

This lone follicle starts producing oestrogen, which thickens the endometrium.

So, progesterone is low, FSH is high, and oestrogen is rising. Testosterone is rising too, but in lesser amounts.

Low progesterone levels may lead to higher levels of inflammation in the body. But, at the same time, higher oestrogen levels may help us feel more energised, better able to deal with pain, and more positive and sociable.

Summer: the ovulatory phase

Midway through the cycle (about day 14 on average), rising oestrogen levels trigger the release of luteinising hormone (LH) and reduce the amount of FSH being released.

This LH surge is responsible for ovulation; the mature follicle bursts to release its egg, which travels down the fallopian tube to await fertilisation.

Some people say they feel a twinge of pain when they ovulate; many don’t feel anything at all.

A few days before this, cervical mucus changes to become ‘sperm-friendly’ and vaginal discharge becomes thick and sticky, like egg whites.

“In theory,” says Marilyn Glenville, “a woman could have intercourse on a Monday and ovulate on the Friday and still get pregnant, because that change in the mucus can keep that sperm alive for up to five days.”

The ovulatory phase includes these days of fertility, not just ovulation itself. Oestrogen and testosterone are at their highest, and progesterone begins to rise.

Our energy levels and libido are likely to be elevated, and we may take more pride in how we look.

Autumn: the luteal phase

If the egg is not fertilised, it degrades a day or two after ovulation. The empty follicle that released it becomes a ‘corpus luteum’ – a temporary hormone gland – which begins pumping out progesterone, and some oestrogen too. The endometrium gets thicker.

During this phase, energy levels fall; it is common to feel sluggish or forgetful.

Those with diabetes may find their glucose levels more difficult to control.

As another period approaches and progesterone builds, some people experience PMS symptoms. These may include:

  • Sore, swollen or tender breasts
  • Bloating and disrupted digestion
  • Mood swings and irritability
  • Headaches or migraines
  • Decreased metabolism, weight gain
  • Food cravings
  • Tiredness, sluggishness
  • Changes in sex drive
  • Trouble sleeping
  • Higher body temperature (sweating, feelings of excessive heat, higher risk of dehydration)
  • Fluid retention
  • Increased sensitivity to pain

Right at the end of autumn, progesterone and oestrogen drop and another winter begins.

Tricky transitions during the menstrual cycle

It is clear that certain days of the menstrual cycle may bring more challenges than others. In particular, stages of transition – especially the end of autumn and onset of winter – may be more of a struggle as the body goes through hormonal withdrawal.

But good nutrition can help, says Glenville.

“The drop of progesterone is actually signalling the bleed, the period, to start,” she says. “And it’s that change where most of the symptoms that the woman is going to feel will happen.”

Glenville says that PMS is a syndrome that includes 150 different symptoms that appear just before the period.

“It’s really quite a broad spectrum of – yes, the mood swings, anxiety, tension, aggressive outbursts – but there can be a lot of fluid retention, so breast tenderness and swollen fingers so rings don’t fit, depression…

“And for some women it can start up to 10 days before the period actually kicks in.”

Menstrual migraines

“One of the [symptoms] that’s very common,” says Glenville, “are the menstrual migraines. That’s where a woman may get – it may be a headache or it may actually be a migraine – the day before or the [first] day of the period.”

Migraines affect 17% of women – compared to 5% of men – and maybe as many as half of all women who seek clinical treatment for migraines report a link between their symptoms and cycles.

The suspected cause is oestrogen levels plunging just before the period begins.

In fact, some research suggests that women who get these menstrual migraines experience a more rapid drop in oestrogen in the days before their periods, compared to women who do not.

Glenville says that it’s the liver that often struggles with the hormonal shift.

“All of our hormones have to be detoxified by our liver,” she says, “and that particular time of the month is a big transition where the hormones are shifting over.

“So the liver’s got to deal with that, and if a woman hasn’t been looking after herself, or drinks a lot of alcohol, or just doesn’t detoxify her hormones efficiently, that’s when we see these menstrual migraines.

“Usually nutritionally we can eliminate them.”

Inflammation and immunity during the menstrual cycle

Another tricky aspect of the cycle can be the waxing and waning of inflammation, largely caused by fluctuating levels of progesterone, which is anti-inflammatory.

Inflammation is often worst during winter (the period), when progesterone is at an all-time low and inflammatory substances called prostaglandins are sent to the uterus.

Prostaglandins break down the endometrium (womb lining), encourage it to leave through the vagina with contractions (cramping), and heal blood vessels in the uterine wall.

But these processes can also inflame nearby organs such as the gut. Glenville says: “Because in women the reproductive side and digestive side are very close together, [inflammation] can affect the digestive system too.

“And so there can be a lot of cramps and digestive issues, gastrointestinal discomfort…There may even be changes in bowel motions as well, so constipation or diarrhoea.”

She mentions that, because of the close relationship between the gut and the brain, this inflammation can negatively affect mental health too.

For those who have underlying inflammatory conditions, such as arthritis or chronic pain, Glenville says their “other symptoms may be magnified” during winter and spring.

But the other side of the coin is that high progesterone suppresses the body’s inflammatory response, which can impair the efficiency of the immune system.

Coughs, colds, infections and viruses may be easier to catch during summer and autumn (from ovulation to the period), and those for whom immunity is a problem may want to be more careful during these phases.

Optimising your cycle

Glenville has a lot of advice on how women can support their bodies through these trickier phases.

Firstly, she says, focus on blood sugars. Our blood sugar levels may fluctuate more drastically during autumn, when our bodies tend to be less sensitive to the hormone insulin.

And, when blood sugar drops, the body produces adrenaline and cortisol – the ‘stress’ hormones.

See our articles on blood sugars and insulin sensitivity:

“We know cortisol competes with progesterone,” she says. “So even if [a woman with PMS] is producing the correct amount of hormones at the right time, cortisol has priority in terms of the receptors, so [if she’s stressed] her body can’t use that progesterone efficiently. It could leave her oestrogen dominant.”

Oestrogen dominance, Glenville says, could negatively impact fertility and conditions such as endometriosis and fibroids, and increase the risk of miscarriage in the event of pregnancy.

Cortisol is released whenever we feel stressed, so Glenville recommends trying to address our stress levels too.

Phytoestrogens, Glenville continues, are really important. “Although the name implies they’re going to have an oestrogenic effect, they don’t; they actually have a balancing effect on hormones, so they can be really useful.”

Phytoestrogens are in chickpeas, hummus, soy (and soy-based products such as tofu, tempeh and soy milk), flaxseeds, lentils, and plenty of other plant-foods.

To help with inflammation, she recommends concentrating on omega-3. These can be found in olive oil, oily fish, eggs and walnuts.

The typical Western diet contains “too much of the omega-6s”, says Glenville, “and not enough of the omega-3s, and it’s our omega-3s which are anti-inflammatory”.

Some people who experience period pain and digestive issues may benefit from cutting down inflammatory foods, such as refined carbohydrates, sugars and highly processed foods – and maybe even dairy and gluten too.

“All of the food recommendations – it has to go on all month,” says Glenville. “It can’t just happen in that luteal phase [autumn], because the cycle is one entity.”

Different food for every season?

But Le’Nise Brothers – author of You Can Have a Better Period – is keen to advise people to fine-tune their nutrition and lifestyle practices, matching different foods to different phases.

In winter, she suggests focusing on iron, to replace the iron lost through menstrual blood, and copper, to help the body absorb iron.

During spring, she says that supporting the liver with detoxification can be beneficial, as hormone levels rise. This could mean drinking less alcohol perhaps, eating lots of cruciferous vegetables, or eating plenty of fibre to encourage regular bowel movements.

For summer (ovulation), Brothers recommends concentrating on nutrients such as selenium, zinc, omega-3 and vitamin D.

And finally, during autumn, she says magnesium can benefit those who experience PMS.

To find out more, listen to our interview with Brothers on the Optimum Nutrition podcast.

Glenville, however, believes that “it is more important for the woman to eat consistently well throughout the cycle, because what happens in one phase of the cycle will have an effect on the cycle as a whole”.

“For example,” she says, “the womb lining (endometrium) is being built up in the follicular phase [spring] so if this is too thick then bleeding will be heavier when the period comes, and more iron will be lost.

“So, it would be important to focus then on why the endometrium is too thick rather than just aiming to ‘treat’ the symptom of iron loss because the period is heavy.”

Hacking your periods

Yet some people may change their behaviour over the course of their cycles.

For example, it makes sense to train harder at the gym during spring and summer (just after the period), because that’s when it’s easiest to build muscle, push through pain, and enhance strength.

And studies have suggested that, for those wishing to conquer addictions – such as smoking, drinking or sugar – they may find more success if they begin in their autumn (pre-period).

Glenville says that adapting our calendars to fit our cycles may or may not be helpful.

“I think it just depends on how that woman feels in her menstrual cycle. So if she finds the moods difficult, very stressful, then yes, it would be better to push things into the first half.

“For some in the creative field, the luteal phase [autumn] is when they feel the most creative. They feel different. It sparks different ways of thinking.

“I remember one lady in the clinic said that she waits till the luteal phase [autumn] to take everything back to the shops that she’s not happy with, because she feels like she can argue more and be a bit more aggressive.

“Women get in tune with their body. Use the cycle as you need to. I think we just want to be careful about being ruled by our cycle.”

Enjoyed this article?

Learn about the health benefits of oranges

For articles and recipes subscribe to the Optimum Nutrition newsletter

Discover our courses in nutrition