Saltier eating habits came with about 1.5 times the odds of bothersome hot flushes in 3,664 midlife women. Three questions did the sorting

Hot flushes and night sweats are usually put down to hormones, and hormones are certainly most of it. But somewhere between half and three quarters of women get them, some far worse than others, and researchers keep looking for everyday habits that tip the balance. A cohort study published in Nutrients on 31 October looked at one that rarely comes up: how salty a woman eats.

The women came from the Korean Longitudinal Study of Midlife Women, run at a large health screening centre in Seoul. They joined between 2014 and 2018, aged 42 to 52, still having periods or only just starting to see changes, and not on hormone therapy. They were followed with questionnaires every one to two years until July 2024. After exclusions, 3,664 women were analysed. Their average age at the start was 45.6.

Salt was not measured in urine or food diaries. Instead the women answered three short questions: how salty they thought their eating was, whether they added salt or soy sauce to food that was already cooked, and whether they ate fried food with soy sauce. The answers added up to a score from 0 to 36, and the researchers split the women into three groups: 10 or under, 11 to 16, and 17 or over. Hot flushes, night sweats and sweating were scored with a standard menopause questionnaire, and the outcome was whether these were, on average, bothersome. At the start, about 1 in 5 women were already in that range.

Over the follow-up, women in the middle and top salt groups had about 1.5 times the odds of bothersome symptoms compared with the lowest group (odds ratios 1.48 and 1.51). That held after allowing for age, menopausal stage, smoking, exercise, education, body mass index and high blood pressure, and it held when women with high blood pressure were left out. When the salt score from one visit was used to predict symptoms at the next, the top group still stood out (odds ratio 1.64), though the middle group no longer did.

There is a curious detail in the body-fat results. Among women with 35% body fat or more, those in the top salt group had more than twice the odds of bothersome symptoms (2.24). Among leaner women, the odds rose from the lowest to the middle group and then stopped climbing. The authors are careful here: once they corrected for testing several body measures at once, the difference between the two groups was not statistically convincing, so they call it exploratory.

The weak spot is the exposure itself. In the study that first built these three questions, the total score lined up only modestly with sodium in a 24-hour urine sample (a correlation of 0.26). More than 1,100 women were dropped because they skipped the optional salt questions, and over half of those analysed had only one visit. Women who salt their food heavily may also differ in other ways, from processed food to coffee to vegetables, and diet quality was not recorded. The authors call the findings hypothesis-generating, and say only a trial that actually cuts salt could show whether that eases hot flushes. For now, current menopause guidelines don't list salt reduction as a treatment for them.