The first studies to examine the sleep-inducing effects of a specific food date back to the 1970s. I think many of us remember the malted milk drink, Horlicks. Using time-lapse cinematography, a group of researchers recorded sleep movements after the consumption of 350 mL of warm water by a group of subjects, compared to another group of subjects who drank 350 mL of warm milk with 5 teaspoons of sugary Horlicks powder added, 30 minutes before going to bed. Another group acted as the control group and had no beverage before hitting the pillow. The study pointed out that none of the participants had a history of sleep disorders. I wonder how many of them were in menopause I thought to myself. But cynicism aside, this study was one of the foundation studies that gave interesting insight into the nutrients that may help people sleep better, because the group who had the milky, sugary drink, had fewer movements between 4am and 7am – their sleep was deeper.
I have no idea if this original research was sponsored by Horlicks … perhaps it was. And I’m unsure whether this research helped to sell a whole lot more Horlicks powder at the time … perhaps it did. But what it did achieve was to foster curiousity about how our sleep is impacted by certain nutrients. Every week I choose a different topic in my private coaching community and this week, the nutrients that have been specifically researched to help us with our sleep, is my topic. With over 1000 women who are in their menopause transition in my coaching group, any topic about sleep gets the thumbs-up! Understanding sleep research is important, but not all of it is relevant to our age and stage. We have unique hormonal changes that affect our sleep and of course, because we are transitioning through mid-life, there are the changes that arise from losing oestrogen and progesterone around other organs that I’m focused on as well. Sleep is crucial to sort out in mid-life. If we don’t then it’s a slippery-slope to other health changes that arise as we get older. That’s why this week I’ve been diving into the sleep and nutrition research and looking at it through a ‘menopause-lens’ and why, today, I’m sharing some of it with you as well. I’m sure if you are in menopause, then you may be troubled with not sleeping … it’s happened to many of us. Myself included.
When women come onto my 12 week symptom reduction programme or my 12 week menopause weight loss programme, they not only learn that what we eat before we go to bed matters to our sleep quality and duration, but also when we eat. If you are determined to reduce your hot flushes, night sweats and or manage your energy levels and weight, then this knowledge is important. Not only because more recent studies have shown that our brain and body require certain nutrients overnight in order to heal and restore our health, but also because we are ageing. It is well known in ageing science that changes in our night-time sleep quality occur along with changes to our circadian regulation of the sleep-wake cycle. This makes it doubley tough for women going through menopause who find that they cannot sleep all night. I’ve written about this in some of my previous newsletter articles and talk about this in my Masterclass on Menopause 2 hour webinar, which is now ONLINE for you, now that I can’t travel. The great news is that now it’s online for you, it’s available for you anywhere, anytime and you can pause it and go back to it if you don’t have 2 hours. You also have it available to you for 2 months in your learning area and it is stacked full of great solutions for you as well.
But back to the Horlick’s study. When the researchers found that those who drank the milky Horlicks mixture slept for longer and slept more deeply, they also decided to examine the habitual dietary habits of the subjects too. They divided participants into those who usually ate within 1 hour of bedtime (eaters) and those who did not (non-eaters). The non-eaters slept best. But what was of interest to the researchers, was that the eaters had improved sleep after consuming the Horlicks drink after their food. This lead the researchers to conclude that one’s dietary habits primarily influence the sleep response. More recent research supports that timing of food is important to our sleep and as I say in my porgrammes, when we don’t eat at least 3 hours before bedtime, it gives our ageing digestive system time to do its job and it helps us to sleep longer and deeper. When we eat too much too close to bedtime, we don’t sleep as well. Of course, this may not be news to any of you who have already experienced this over the years – restless night after having wine and cheese evenings anyone?
What nutrients might affect your sleep?
Paving the way to further research about the nutrients that help us sleep, the original Horlicks study was of interest to sleep researchers, especially in the context of middle-age. Malted milk is composed of wheat, malt barley, sugar, milk, and 14 vitamins and minerals, including vitamin D and several B-group vitamins. Emerging clinical evidence on disrupted sleep supports the association between vitamin and mineral deficiencies and disrupted sleep. I’m always telling women to get some blood work done if their sleep has been problematic in menopause and if the solutions I have in the MyMT programmes are not working for them, because they might be low in Vitamin D and/or the B-vitamins. In individuals with low serum (blood) concentrations of Vitamin D there is evidence that sleep becomes disrupted. (Qi Gao et al, 2018). Fatty fish may help with this. Fatty fish (>5% fat) is a good source of vitamin D and omega-3 Fatty Acids, which are now known to provide us with nutrients that are important for the regulation of serotonin and therefore sleep regulation. Serotonin is an important mood hormone, which goes low in menopause and many of you may be on anti-depressants because of your low serotonin. If you aren’t sleeping though, then your low serotonin is also the problem. Serotonin helps to make melatonin.
There is also some evidence with regard to the influence of B vitamins on sleep especially Vitamins B12 and B6. Emerging studies show that Vitamin B-12 affects plasma melatonin concentrations and is also associated with improvements in sleep quality. But be warned – there are other studies that show that too much B12 also keeps you awake at night. Balance is everything.
The other vitamin that may have a helping hand with sleep quality is Vitamin B-6. This lesser known vitamin serves as a cofactor (helper) in the production of our mood hormone called serotonin from 5-hydroxytryptophan (5-HTP). Therefore, Vitamin B6 has emerged as a helper-vitamin to assist in the production of our lovely sleep hormone, melatonin. But don’t rush out and buy supplements – it seems that sourcing our B-vitamins from food is more important than supplements.
Let’s eat some fruit to help our sleep!
It concerns me when I hear about diets that inform women to not eat fruit. Yes, I ‘get it’ from the perspective of weight loss and reducing insulin, but when it comes to sleep, mid-life women need to be cautious about messages to get off beautiful Vitamin C-enhancing fruit. Not only do we need Vitamin C for our joints, but we also need it for our sleep. Kiwifruit and cherries get a special mention in sleep research too.
Studies that have looked at the consumption of fruit on sleep promotion have been emerging for a number of years. The melatonin and phytonutrient profile of tart cherries is often associated with their health and sleep benefits because tart cherries have a high dietary melatonin concentration. But there is something else as well. Tart cherries have also been shown to exhibit anti-inflammatory characteristics that may be beneficial in improving sleep quality. If you are an exerciser, then the cherry juice might just also help you with improving glucose uptake into your muscles. If you’ve been waking to restless legs at night, then you might like to give this a try. I know that some of the women on the MyMT programmes have tried cherry juice and find it beneficial. But so too is kiwifruit.
As a ‘Kiwi’ I like promoting kiwifruit – especially if the science tells us that it will help us to sleep for longer. Although further research into the sleep-promoting
mechanisms of kiwifruit is needed, several explanations for the effects of kiwifruit on sleep exist. One of the reasons given is that the high antioxidant capacity and serotonin and folate content of kiwifruit may contribute to the observed
sleep benefits of kiwifruit consumption.
Kiwifruit is also a good source of vitamins C and E, both of which protect against
the damaging effects of inflammation. I’m always explaining to women that inflammation that has been accumulating for decades is the source of our worsening symptoms in menopause especially for those who are and have been regular exercisers for years. We are the first generation to go into menopause in the context of all the sporting and fitness industries. That’s why eating a diet that helps to reduce inflammation is an important component of the MyMT™ programmes and follows my research on women’s healthy ageing. Kiwifruit is also high in folate and folate deficiency has been linked to insomnia and restless leg syndrome – something many of us have experienced as we arrive in menopause.
In my design of the MyMT™ online 12 week programmes, I have only looked through the lens of menopause and our ageing. Since undertaking my doctoral studies on women’s healthy ageing, it has lead me down a fascinating minefield of discovering the science of ‘how’ we look after ourselves at this life stage. When I received this email from Nicky this week, who watched my Masterclass on Menopause, I was so heartened,
“I watched your webinar last night. I will be forever grateful to the friend and health colleague who sent it to me and I will be signing up for your programme as soon as I’ve written this email. It’s the best $15 I think I have ever spent. So many introductory webinars are complete time wasters but you gave so much value in the webinar and the research you have undertaken to help so many of us at this time of life is mind-blowing.”
When my own symptoms overwhelmed me, I found that too many lifestyle programmes don’t take into account our age and stage of life. Many are designed by men for men. But when it comes to ‘men-opause’ it’s an entirely different story. So if you aren’t coping with your heat regulation, sleep, anxiety, depression, weight or joint problems as you move through menopause and beyond, then will you join me? No matter where you live in the world, I would love to support you to feel like your old-self again. Whilst my Covid-19 special promotion ended last weekend, I still have a discount for you with savings of NZ$50, because I know so many of you are still experiencing challenges with your work situation and stress levels.
This makes is NZ$249 [AUS $235 and UK£130]. There is also a monthly payment option you can choose. Please use the promo code MyMT2020 when you select the programme that best suits you.
Dr Wendy Sweet, [PhD] Women’s Healthy Ageing Researcher & MyMT Founder & Coach. Member: Australasian Society of Lifestyle Medicine.
Grandner M., Jackson N., Gerstner J., Knutson K. (2014). Sleep symptoms
associated with intake of specific dietary nutrients. J. Sleep Res. 23:22–34.
Murphy R., Carnethon M., Harris W., et al. (2019). Omega-3 and omega-6 Fatty Acid Biomarkers and Sleep Duration: Pooled Analysis from Five Prospective Studies in the Fatty Acids and Outcome Research Consortium (FORCE) (P08-116-19). Curr Dev Nutr. 3(Suppl 1):nzz044.P08-116-19.
Gao, Q., Kou, T., Zhuang, B., Ren, Y., Dong, X., & Wang, Q. (2018). The Association between Vitamin D Deficiency and Sleep Disorders: A Systematic Review and Meta-Analysis. Nutrients, 10(10), 1395. https://doi.org/10.3390/nu10101395
Southwell P., Evans C., Hunt J. (1972). Effect of a hot milk drink on movements during sleep. British Medical Journal, 2:429–31
St-Onge, M-P., Mikic, A., Pietrolungo C., (2016). Effects of diet on sleep quality, Advances in Nutrition, 7(5), 938–949, https://doi.org/10.3945/an.116.012336