Does Soya Cause Cancer?

Firstly, what is soya? Soya beans and products have become a hot topic recently in the rise of more plant-based diets and in particular the link between soya and cancer. Soya beans are are a popular, and cheap legume, native to East Asia. Soya contains a good amount of protein, fibre, potassium, magnesium, copper and manganese. It is also one of the few plant foods with all the amino acids your body needs to make protein, plus, they are a good source of healthy fats, containing both the omega-6 (linoleic acid) and omega-3 (alpha-linolenic) types. Soybeans can be found in many forms, including tofu, the beans themselves (also called edamame), soy milk, miso, and soy powder.

What are the concerns?

Concerns have been raised due to the fact that soya has weak oestrogen (female hormone) like compounds called isoflavones naturally occuring in them. It’s thought that oestrogen can promote the developement, growth and spread of some cancers, and so research has been conducted into whether soya and cancer are linked, and in particular, breast cancer.

What does the research say?

One small study conducted in 2014, suggested that for some women, adding a medium amount of soy to their diets turns on genes that can cause cancer to grow.

The study involved 140 women who were newly diagnosed with stage I or stage II breast cancer between 2003 and 2007. For 2-3 weeks prior to surgical removal of the cancer, the women were randomly assigned to eating:

soy protein (70 women) approx. 50g
a placebo that looked like the soy protein (70 women) approx. 50g

Once the cancerous tissue had been removed and analysed, the results showed that several genes that encourage cell growth were turned on in women in the soy protein group. However, as with most research, ther study had limitations. The study didn’t last long enough to know whether these genetic changes would cause cancer to actually grow. The study also didn’t look at whether soy does or doesn’t reduce the risk of breast cancer, or whether eating soy would have any effect on women who don’t have breast cancer.

The researchers could not conclude that soy should be avoided, and they could therefore not confirm a clear link between soya and cancer.

So should I avoid it?

The current advice is no. The American Institue of Cancer Research and the World Cancer Research Fund for cancer prevention have reviewed the evidence extensivley in this field. Evidence shows that soya does not increase the risk of breast cancer, breast cancer recurrence, or any other cancer. Soya and cancer, and it’s possible effects on health is an active area of research.

How much can I have?

In general, it is fine to eat moderate amounts of soy foods – about one to three servings per day as part of a balanced diet (a serving is about a half cup). If you’ve been diagnosed with breast cancer and are concerned about any isoflavone effects, ask your doctor or a Registered Dietitian for further and more individualised advice.

In summary

Research on soya and cancer, and soya foods is ongoing, but it is clear that soya is nutritious, safe and healthy. Other potential health benefits include lowering cholesterol and even reducing the severity of hot flushes in women going through the menopause. Soya foods can also help us to achieve an increasingly plant based diet by reducing our intakes of animal protein which can also benefit the environment and food sustainability.

Links to further information on soya and cancer:

World Cancer Research Fund Breast Cancer Prevention

World Cancer Research Fund – General Guidance

American Institute of Cancer Research

Craving carbs before your period – Is there any science?

Article edited & republished March 16th 2021

Craving carbs before your period – Is there any science?

Do you find yourself craving carbs before your period? Is PMS sabotaging your ability to eat well? So many people who menstruate experience food cravings and an increased appetite around menstruation. Is there actually a science-backed link between periods and food cravings or is it all just in our heads? Let’s #StripTheNonsense and discuss what might be causing those food cravings, as well as some strategies to manage them.

PMS Explained

Premenstrual Syndrome (PMS) can be characterised by various symptoms in the 1-2 weeks before your period. They are usually relieved a day or so after bleeding begins. These include mood swings, irritability, increased appetite, carbohydrate and alcohol cravings, breast tenderness, headaches and bloating. Some of us get intense symptoms and lots of them, whilst other people won’t notice any.

Prior to menstruation, progesterone and oestrogen levels fall; this is what causes our uterine lining to shed and bleeding to occur. The sudden drop in hormones is associated with the onset of PMS symptoms.

Do all people with cycles tend to eat more around their period?

You are not alone if you find yourself with a ferocious appetite or craving carbs before your period. Below, some of my clients describe their experiences around that time of the month:

“I definitely have a week of my cycle where I am much hungrier and also much more emotional at the same time – which when I am judging myself does not always end in kindness…”

“When my hormones change throughout the month I notice I’m grumpy/sad/tired. I’ve also noticed a link between my mood and not eating intuitively or (more accurately) numbing my feelings with food”

A review of 30 studies (Dye et al. 1997) looked at women’s energy intake at different phases of the menstrual cycle. They identified, that in 27 out of 37 groups of women, energy intake was higher in the second half of the menstrual cycle (day 14-28), before their period was due.

It demonstrates how common increased appetite and food cravings are around our periods. Some research suggests that this could be because calorie requirements may be slightly higher at this time. However, the results are varied and further studies need to be conducted in humans. More research is also required to determine whether sex hormones interact with hunger hormones to control changes in appetite over the course of the menstrual cycle. Hunger hormones tell us when we are hungry, and when to stop eating.

Craving carbs before your period – what types of food are we most likely to crave?

Can’t stop thinking about sugar or find yourself craving carbs before your period? This is certainly the case for many of my clients so if you find yourself in the same boat, rest assured you’re not alone.

The science on the types of foods we tend to crave is inconsistent (Davidsen et al. 2007). Different studies have determined that in the build-up to our period (1-2 weeks), our intake of all three macronutrients (carbohydrate, proteins, and fats) is increased. Two studies have identified that chocolate cravings seem to be more frequent in the build-up to a period, than at any other time of the cycle (Hetherington et al. 1993, Rozin et al. 1991).

In reality, it is challenging to interpret data when it comes to what type of foods we crave. For example, say we crave and end up eating a doughnut, was it the carbohydrate, or fat in the doughnut that we were after? Who knows!

4 Tips to combat increased appetite and cravings

Keep those blood sugar levels steady:

Our blood sugar levels are influenced by what, and how regularly we eat as well as certain hormones. Levels of hormones that affect our blood sugar levels change throughout our menstrual cycle. This may contribute to wanting more food and cravings around our periods. We can help to combat blood sugar fluctuations and craving carbs before your period by:

a) Eating regularly: Try to eat something every 3-4 hours to help prevent dips in your blood sugar. Most people find that leaving more than 4 hours between meals can result in feeling overly hungry, which may result in overeating later in the day.

b) Choosing Low Glycaemic Index (Low GI) foods– Ensuring each meal and snack contains low GI carbohydrates may help with PMS symptoms by maintaining an even blood sugar level and lowering inflammation. Such a diet may also help reduce food cravings. See here if you would like to learn more about GI.

c) Eating protein and fats with your meals – and ideally your snacks too. When a meal contains protein, fat and low GI carbohydrates, this contributes to keeping blood sugar levels stable. It also promotes feelings of satisfaction after eating. Protein can keep us feeling fuller for longer as they mix with the carbohydrates in your stomach, and slow down their absorption. Fats provide flavour and contribute to satiation. If you feel satisfied and full from your meals and snacks, you’ll be less likely to experience cravings.

2. Don’t restrict yourself

Restricting the amount or types of food we eat is guaranteed to lead to eating past the point of comfortable fullness down the line. It can lead on to feelings of guilt and shame and feeds into the diet cycle.

Labelling foods as ‘good’ or ‘bad’ is also a big factor that can lead to feelings of restriction. Of course some foods are more nutritious than others, but labelling foods as bad and good can make you feel good for eating the ‘good food’ and bad for eating the ‘bad foods’. This can again fuelling into the diet cycle.

Rather than labelling foods as ‘good or bad’. try using ‘every day foods’ and ‘celebratory/occasional foods’. Or just call the food by its name. E.g. an apple, or a croissant. It’s normal and healthy to enjoy delicious celebratory or comforting foods alongside nourishing your body with good quality foods that you enjoy.

3. Give yourself some grace

We have already seen how normal PMS symptoms, including appetite changes and cravings, are. We can certainly take the steps above to minimise contributing hormone fluctuations but remember, people with menstrual cycles are cyclical creatures. We can choose to see our fluctuating moods, emotions and appetites as curses. But the end of the day they are natural.

What if, we chose to see these symptoms as an invitation to slow down, rest, listen to and be with our bodies?

When we try to resist what we are feeling and will it away, often we actually create more tension. This may lead to us feeling worse and perhaps increase our desire to eat emotionally which can lead to more feelings of guilt and shame and the cycle continues. Conversely, when we give ourselves some time (even just a couple of minutes) to pause, tune-in and sit with our feelings, they will usually pass. For more information on emotional eating see here.

4. Take steps to reduce stress levels

Stress is also a big one that can affect pretty much all of our bodily functions, including our menstrual cycle hormones. Stress reduction techniques like diaphragmatic breathing, mindfulness meditation and nature walks alongside regular physical activity and getting 7-8 hours sleep each night can help reduce stress and the severity of PMS symptoms.

So in summary…

When it comes to periods and in particular, craving carbs before your period, you are not on your own. Whilst in the two weeks lead up to your period, you may find that you feel a little more hungry, we do not know whether this is the body actually needing more energy, or whether it’s just our hormones causing cravings. More research is required. But don’t worry, there are still things you can do, and I have provided you with some top tips to ensure you feel equipped to nourish your body with what it needs and take care of yourself around that time of the month.

If you battle with PMS-related food cravings, click here to download my free Period Self Care Guide, to learn more strategies to nourish yourself during that time of the month.