A LOW-FAT, PLANT-BASED DIET (RICH IN SOY) MAY be as effective as hormone replacement therapy for reducing hot flashes. While we need validating studies to determine the impact of diet on reducing menopausal symptoms, the dietary approach holds promise.
Hot flashes are the most prevalent menopause symptom and are feelings of intense warmth plus sweating, flushing, and chills. Sweating is typically in the face, neck, and chest. Hot flashes typically last approximately one to five minutes, with some lasting as long as an hour.
Hot flashes are common — upwards of 80 percent of menopausal women in the United States experience them. The hot flashes typically begin shortly before menopause, although for some, they start after menopause. The flashes are usually due to menopause; less commonly, hot flashes occur because of a medical condition such as carcinoid syndrome.
Today, I would like to explore some information about hot flashes, including a 12-week clinical trial that examined a plant-rich diet’s effectiveness in fighting hot flashes.
Hot flash risk factors
Hot flashes (sometimes referred to as vasomotor symptoms) are the most common complaint during the menopausal transition. As many as four in five women experience them.
Many women volunteer that symptoms increase during the transition to menopause. Approximately 40 percent will experience hot flashes in the early transition, but up to 80 percent report having them by late menopausal transition and early postmenopause.
Frequency varies by culture and ethnicity. For example, African American women report more hot flashes than white women, and Japanese and Chinese women report fewer. While many describe the hot flash problem as severe, only about one in four see medical attention.
Here are some other risk factors for hot flashes:
- Obesity. Postmenopausal women who are obese have higher blood levels of estrogen (estrone) than thinner women. In women with a higher weight, fat cells have more conversion of testosterone (androstenedione). Paradoxically, this higher blood level of estrogen is associated with hot flashes. Weight loss can improve hot flashes.
Among women who were overweight or obese and had bothersome hot flushes, an intensive behavioral weight loss…
- Cigarette smoking. There are numerous reasons why women who smoke should kick the habit, but here’s one more: Women who smoke have more hot flashes as they transition through menopause. This connection is especially true for women who carry certain gene variations linked to estrogen metabolism and susceptibility to environmental toxins.
- Reduced physical activity.
- Hormonal concentrations. The prevalence and frequency of hot flashes are associated with blood levels of follicle-stimulating hormone (FSH).
- Socioeconomic factors. Those with less than a high school education and those with difficulty paying for basics have a higher frequency of hot flashes.
Hot flash duration
Many women assume that vasomotor symptoms such as hot flashes will last only a year or two. Unfortunately, such problems tend to last longer. The best estimate of hot flash duration is from the Study of Women across the Nation (SWAN).
Here are the numbers:
- The median duration of vasomotor symptoms (such as hot flashes) was 7.4 years, lasting 4.5 years after the last menstrual period.
- Women who were premenopausal or early perimenopausal when they first experienced vasomotor symptoms (such as hot flashes) had the longest total duration (more than 11.8 years after the final menstrual period median duration of 9.4 years).
- African American women had the longest vasomotor symptom duration (10.1 years), while Chinese and Hispanic women had the shortest (five years).
The Penn Ovarian Aging Study showed an average moderate/severe hot flash duration of about five years. Still, one-third continued to have moderate or severe hot flashes for ten years after the final menstrual period.
You may be surprised that nine percent of women still have hot flashes at 72.
Hot flash physiology
Widening of blood vessels in the skin, or peripheral vasodilation, manifests as high blood flow and temperature during a hot flash. These skin temperature elevations occur in the face, arms, chest, abdomen, back, legs, and digits.
As metabolic rate occurs during a vasomotor event, there is a small rise in heart rate, about seven to 15 beats per minute.
Why do hot flashes occur? Did you name estrogen as the culprit? Perhaps you are aware that estrogen therapy virtually eliminates hot flashes. And that women who undergo menopause (when hormones such as estrogen decline significantly) usually experience hot flashes.
But estrogen drops alone don’t explain hot flashes, as we see no relationship between blood, urinary, or vaginal levels of the hormone and hot flashes. Moreover, there are no differences in plasma levels between women who experience hot flashes and those who do not.
We need to turn to the hypothalamus, our master gland, to understand the phenomenon of hot flashes better. The hypothalamus perches deep in your brain and is our smart control coordinating center. Its main job is to keep a body in a stable state, or homeostasis.
Your hypothalamus helps to regulate your:
- Thirst and hunger
- Blood pressure
- Sense of fullness when eating
- Sex drive
How does the hypothalamus do its job? It directly influences our autonomic nervous system and regulates hormones.
Hot flashes are mediated by temperature regulation (thermoregulatory) dysfunction in the hypothalamus, a state induced by estrogen withdrawal. For women with hot flashes, the so-called thermoneutral zone is narrowed.
While premenopausal women initiate mechanisms to get rid of heat when the core body temperature rises by 0.4°C, this initiation occurs with a much lower increase in temperature in menopausal women.
The warmth sensation occurs because of the inappropriate widening of blood vessels close to the skin. With sweat comes rapid heat loss, and the body’s core temperature drops below normal. Many women then experience shivering as the body tries to restore its core temperature to normal.
Adult estrogen levels, followed by withdrawal, are required for hot flashes. Prepubertal girls have very low estrogen levels but don’t get hot flashes. Low estrogen alone is not sufficient to have hot flashes.
Hot flashes: Fighting back with a plant-rich diet
A recently reported study shows that diet changes can be remarkably powerful for treating hot flashes. Here are the key findings:
A plant-rich diet dropped moderate to severe hot flashes by 84 percent (from nearly five each day to fewer than one daily). The diet may have contributed to helping women lose eight pounds (on average) and improving their quality of life.
A remarkable three out of five women became free of moderate-to-severe hot flashes with a plant-rich diet. If one includes mild hot flashes, the hot flash frequency diminishes by 79 percent. The control group experienced no improvements.
Many subjects in the diet intervention group also reported improvements in mood, sexual symptoms, and overall energy.
The WAVS trial — the Women’s Study for the Alleviation of Vasomotor Symptoms study–shows that diet has much greater efficacy in treating hot flashes and night sweats than scientists had previously thought.
Rather than using hormone medications, researchers tested a combination of a low-fat plant-based diet plus one-half cup of ordinary soybeans added to a salad or soup daily. Let’s get to the details.
Hot flash study details
Researchers randomly assigned postmenopausal women experiencing at least two hot flashes daily to one of two groups:
- Low-fat, vegan diet (including half a cup of cooked soybeans daily)
- Control group (no dietary changes for 12 weeks).
The women recorded the frequency and severity of their hot flashes using a mobile application. They also completed the Menopause Specific Quality of Life Questionnaire (MENQOL) to evaluate physical, psychosocial, and sexual symptoms.
Participants also used a study-provided digital self-calibrating scale to track body weight during the day. The intervention group members also received an Instant Pot to prepare soybeans at home. Finally, the group gathered with the research team weekly via Zoom.
Hot flashes and diet — My take
Historically, nothing (other than estrogen) has done as much as this diet intervention for hot flash reduction. I hope we see larger trials to confirm the results and better understand soy’s contribution to reducing hot flashes.
The study has some limitations, including its cohort study design. I prefer to see a double-blind study to prove causality. The study’s small sample size indicates the possibility of a placebo effect. Still, a healthy diet generally helps us to feel better and reduce our risk of cardiovascular diseases.
Finally, several of the study’s authors got compensation from the Physicians Committee for Responsible Medicine for their contributions.
Diet — Getting started.
Do you want to improve your diet? Or knock down hot flashes? Here are three steps you can take:
- Embrace a vegan diet. Incorporate whole grains, fruits and vegetables, and legumes such as beans, lentils, and peas.
- Limit high-fat foods. If you consume packaged foods, keep the fat to less than three grams per serving.
- Consume one-half cup of cooked soybeans daily. You can prepare dry soybeans with a pressure cooker or on the stove. Or consider buying already cooked soybeans in a can. Prepare them in the pressure cooker and roast them, baking them on a parchment-lined baking sheet at 350 F for an hour or until dry and nicely browned. You now have a snack, salad topper, or soup additive.
For those opting for a vegan diet, please consider vitamin B12 supplements. And don’t forget to track your weight, hot flash frequency, and hot flash severity.
Thank you for joining me to look at hot flashes and diet.