Sleep is indispensable for health and is a basic human need just like food, clothes and shelter for the survival of human beings. Sleep is a homeostatic process that involves an active and periodic biological state that’s important for physical and mental health still, we don’t pay much attention to it and end up suffering from debilitating side effects. It also helps with stress reduction, circadian rhythms and performance of individuals and despite such benefits we see a steady rise in sleep disorders, insomnia problems and other sleep-related issues in the world population. Studies show that sleep quality and sleep length affect mortality rates and most studies quote 7-8 h of sleep at night as the perfect duration to stave off death risk apart from minimizing risk of diseases such as coronary heart disease, hypertension, diabetes and obesity. There are numerous psychological, biological and social factors affecting sleep but topmost of all is diet that remains as one of the most underrated determinant of sleep quality. There are certain studies that show a link between certain nutrients and sleep-foods containing tryptophan raises melatonin levels that are directly linked to regulating sleepiness. Selenium in wholegrains promote longer sleeping hours and shorter sleeping hours is linked to zeaxanthin and lutein that are abundant in green leafy vegetables. There have also been studies showing that functional foods help in rectifying sleep disorder but not even 1% of the population choose to be treated through this means.
We have witnessed an interest in the effects of estrogen on brain functions as this hormone acts on the brain through the same neurotransmitter nerves that are involved in sleep regulation. Hence, we do have research data suggesting that estrogen replacement therapy could be effective against insomnia, nocturnal restlessness and frequent awakening while helping to fall asleep too. Isoflavones are a class of phytoestrogens that have structural similarities to that of 17- β estradiol and a weak estrogenic effect. This phytoestrogen binds to and mediates transcription through estrogen receptors α and β but in the absence of estrogens these isoflavones have a weak estrogenic effect. This also conveys the fact that isoflavones might have beneficial effects on sleep status. A cross-sectional study in Japan identified the effects of isoflavone intake on sleep duration.
Isoflavone Effect on Sleep Duration in Japanese Population
Data from a prospective cohort study was used here where 1833 participants had undergone one of the two health examinations namely lifestyle-related illnesses and health examinations A (this includes blood examinations) or health examination B (does not include blood examination). Those who had undergone lifestyle-related illnesses and health examination A were called to participate in the study and this included 1253 participants. After various exclusion criteria the study was left with 1076 subjects. Dietary intake was measured using a questionnaire that probed into the frequency of intake of 75 food items along with their specified serving size. Isoflavone intake was mostly daidzein and genistein and both of them were found in soybeans. Natto, tofu and fried tofu were the three foods which were predominantly used to measure isoflavone intake and each of the participants revealed the mean frequency of consumption of these foods by checking 1 of 7 frequency categories that was anything among ‘almost never’ to ‘two times a day.’ Nutrient intakes were measured and isoflavone intake was assessed by summarizing them into quartiles: Q1:0-10.96 mg/1000 kcal/day; Q2: 10-97-17.99 mg/1000 kcal/day; Q3: 18.00-26.73 mg/1000 kcal/day and Q4: 26.74-83.06 mg/1000 kcal/day.
Sleep quality and duration was assessed by using questionnaires that included questions such as “How many hours do you usually sleep per day?” for which options provided were <5 h, 5-6h, 6-7h, 7-8h, 8-9h and ≥9h. Further, sleep duration was classified into two classes:7-8 h and <7 h or ≥8 h. Sleep quality was assessed using questions such as “Do you feel refreshed after sleep?” for which options provided was ‘yes’ and ‘no.’ OR ‘Have you used hypnotic drugs in the past month?” and the options again were ‘yes’ and ‘no’. Blood pressure and blood sugar measurements were taken, BMI was measured and metabolic syndrome presence was assessed. Metabolic syndrome was confirmed if the participants had ≥3 risk factors such as abdominal obesity, hypertension, elevated triglycerides, reduced HDL-C and hyperglycemia. Data on all of these were obtained from 1076 subjects of which 143 were classified as having normal sleep duration (7-8h) and 605 (56.2%) were classified as sufficient sleepers with respect to sleep quality. Mean dietary intake of all items (excluding coffee) was significantly high across categories of isoflavone intake. Mean coffee consumption and proportion of subjects who were current smokers were lower across categories of isoflavone intake.
After adjusting for various variables, it was seen that sleep duration increased across categories of isoflavone intake. Those subjects who consumed 26.74-83.06 mg/1000 kcal/d isoflavone in comparison to 10.96 mg/1000 kcal/d of isoflavone had better chances of sleeping for 7-8 h and also their sleep quality was good. The study clearly proves that high doses of isoflavone intake from foods is related to optimal sleep duration (7-8h) and sleep quality. The researchers theorize that the possible effect might be due to estrogen effect on certain neurotransmitters in the brain such as serotonin whose main function is to regulate sleep-wake cycle. Isoflavone might also have an estrogenic effect that benefits sleep quality and it improves cognitive function as well that’s once again related to sleep quality. There are studies that also show that isoflavone intake decreased stress in both men and women aged 22-56 years and antioxidants can improve this. Isoflavones are rich in antioxidants thereby helping in the improvement of sleep quality.
Isoflavone Impact on Post-menopausal Women
Menopause brings about overwhelming changes in the body and lack of sleep is one of them. In a study that followed 12,603 post-menopausal women for 10 years it was found that 46-48% of them suffered from insomnia compared to perimenopausal women (38%). Studies point at hormonal changes in these women to be major factors for such problems and the estrogen is the most commonly associated hormone with sleep patterns. Post-menopausal women sleep more in NREM stage 1,2 and the sleep quality decreases slightly in NREM stage 3 and REM sleep. Estrogen helps in increasing REM sleep, reducing sleep latency, reducing nocturnal awakening and increasing total sleep time.
A study on 169 postmenopausal women showed that isoflavone treatment was effective in improving quality of life and decreasing climacteric symptoms including sleep disturbance. Another randomized controlled study on postmenopausal women with insomnia indicated that there was a notable increase in sleep efficiency in the isoflavone group compared to the placebo group. Despite estrogen’s beneficial effects on sleep quality we have studies reporting that estrogen replacement therapy (ERT) alone will increase risk of stroke and venous thromboembolism. To add to this, in combination with progesterone there is an increase in the risk of breast cancer and heart disease. Though we say that sleep disturbances are a result of hot flashes in post-menopausal women even those women without hot flashes fail to sleep well and sleep long. A study on post-menopausal women was conducted in Thailand. All the volunteers were aged between 45 and 60 years and had a BMI lesser than 30 without history of illness, hormone therapy or substance abuse. The Pittsburg Sleep Quality Index (PSQI) was used to assess sleep quality based on scores- a total score of 5 or below implicated good sleep quality and a score above 5 indicated bad sleep quality.
There were eight cases of participants who were divided into two different groups-group 1 had ≥50 mg of isoflavones (1 capsule had ≥25 mg of isoflavones and hence participants here had 1 capsule twice a day) and group 2 had intake ≥100 mg of isoflavones (hence had 2 capsules twice a day). The average score before intake of isoflavones was 12.50 and the score after intake of ≥50 mg of isoflavones was 8 during the 1st week and 5.75 during the second week. The average score before intake of ≥100 mg of isoflavones per day was 14.75 and the score after 1st week of intake was 10.00 and after 2nd week it was 5.75. The study found that isoflavones intake was instrumental in promoting sleep quality but there was no significant difference found between the two groups which had different intake quantities.
Relationship between Daily Isoflavone Intake and Sleep in Japanese Adults: https://nutritionj.biomedcentral.com/articles/10.1186/s12937-015-0117-x
Beneficial Effects of Isoflavones to Post-menopausal Women with Insomnia: https://www.researchgate.net/publication/325703862_Beneficial_effect_of_isoflavones_to_post-menopausal_women_with_insomnia_A_preliminary_study
AVOID FRAUD. EAT SMART
+91 7846 800 800