July 18th, 2018 , By - Anita Tee
Are you a dairy lover?
Are you also completely confused about whether dairy is actually a good or a bad thing for your fertility and hormonal health?
Well, you’re not alone.
With so many conflicting headlines out there, it can be challenging - if not completely bewildering - to understand what exactly you should be eating; particularly when it comes to supporting your hormonal health, fertility and conditions such as Polycystic Ovary Syndrome (PCOS).
We’ve all heard the ‘full-fat’ versus the ‘skimmed’ milk debates and now it seems like the addition of dairy to the diet as a whole is being brought into question regarding its influences on hormonal health.
That’s why, today, we’re going to break down the research for you and finally answer that burning question: ‘to dairy or not to dairy’ when it comes to fertility and PCOS.
Hint: a little bit of cheese may not be such a bad thing…
The history of the dairy debate
In order to fully understand how we’ve gotten to this point with dairy, it is important to take a look back to when dairy consumption first came into question and, what drove this trend.
Humans first began consuming dairy approximately 8,000 years ago with the introduction of dairy farming (1). Overtime, it became a central part of the human diet, with many cultures producing and consuming fresh milks, cheeses, creams and yogurts on a daily basis.
In fact, dairy was such a valuable part of the diet that owning cows, goats or sheep became a symbol of prosperity in many tribes and villages (2). This belief was equally met with positivity among the scientific community, as dairy was widely praised for being a quality source of calcium and vitamin D which supported the growth of strong teeth and bones (3,4).
However, public perception of the widely consumed full-fat dairy rapidly changed between the 70’s and 80’s when the association between diet and disease was first brought to the attention of the American federal government (5). These health concerns were based on a growing body of scientific evidence dating as far back as the 1940’s which found a correlation between high-fat diets and high cholesterol (5).
Due to the increasing rates of heart disease present at the time, physicians began to recommend a low-fat diet for those at a higher risk of developing heart disease. A change which slowly encouraged the switch from full-fat meat and dairy products to their low-fat counterparts such as skimmed milk, low-fat yogurt and soft cheeses.
By the late 1980’s, the low-fat movement had become the overarching food ideology for health and well-being. It was adopted not just in the United States, but across the world in Europe, Australia and even Asia; promoted by governments, doctors and food companies alike. Millions of people quickly subscribed to the low-fat cause as it became popularised not only for preventing heart disease but, also, promoting weight loss and health management.
However, there was one caveat – it had never been scientifically proven that a low-fat approach was actually beneficial for weight loss and heart disease; just that a very high-fat diet was not good for these conditions.
Apart from these historic misconceptions about low-fat versus full-fat for weight loss and heart health, dairy has more recently come into question for its role in hormonal conditions such as PCOS and infertility.
And, as it turns out, distinguishing between low-fat versus full-fat may still be the key when it comes to deciding whether you should or shouldn’t be consuming your dairy products.
Dairy and Fertility
Traditionally, western medical doctors have recommended pregnant women or women trying to conceive to focus on consuming low-fat dairy products due to their beneficial nutrition content, including high protein and calcium, while also supporting easier weight management due to their lower calorie content.
However, we now know that this is not entirely the case.
In fact, a study published in the Journal of Human Reproduction discovered that daily consumption of low-fat dairy products actually reduced a woman’s fertility by affecting her ovulation patterns (6).
The study followed 18,555 women without a history of infertility who either attempted to or became pregnant over an 8-year period. Interestingly, researchers found that the daily consumption of 1-2 full-fat dairy servings actually had the opposite effect. Researchers suggested that this stark contrast in results may come down to a fat-soluble compound within the full-fat dairy foods which is supportive of ovarian function. Unfortunately, this substance is removed, along with most of the natural dairy fat when low-fat or skimmed milk is produced (6).
Dairy and PCOS
By far, one of the most controversial areas of discussion around dairy consumption and hormonal health has been when it comes to PCOS. However, when discussing the impact of dairy on PCOS, it is important to be aware that the research regarding how dairy affects PCOS is still extremely limited.
In a study published in the International Journal of Preventative Medicine, it was discovered that women who suffered with PCOS tended to consume a greater amount of low-fat and fat-free dairy foods (7). With that being said, these results were based on self-reported milk intake, without looking at other dairy-sources such as cheese and yogurt (8,9). In addition, this type of self-reported data is seen as a poor standard of evidence when it comes to the scientific method (10).
Furthermore, researchers also failed to compare these numbers with women who consumed full-fat dairy; for which previous studies have found it to have a positive association with fertility and birth outcomes (11).
Another study published in the Journal of Obesity Weight LossTherapy demonstrated the benefits of a low-starch and low-dairy diet for women with PCOS however, once again, the study group assessed was very small – with only twenty-six women in total (12).
While we can see that a diet filled with low-fat dairy may not be the best thing for women with PCOS, the evidence is still very limited regarding whether full-fat dairy has the same effect. As you can see from the studies on dairy and fertility above, there is a difference between low-fat, fat-free and full-fat dairy when it comes to hormonal health and fertility. In fact, many experts suspect that the reason low-fat dairy may be contraindicated for women with PCOS is down to its significantly higher sugar content (13). For now, it’s important that you listen to your body when it comes to dairy and pay close attention to how you react.
For some women, moderate dairy consumption appears to be completely fine, while others may discover a sensitivity or intolerance (14,15). That being said, it does appear that low-fat dairy might contribute to symptoms such as acne (16) therefore, if this is an issue for you, dairy might be best avoided. If, however, you don’t find that dairy breaks you out, stick to full-fat sources which have not been proven to have the same negative impact.
Dairy and IVF
In a study published in the Journal of Human Reproduction, researchers investigated the relationship between dairy intake and in-vitro fertilization outcomes among women in a fertility clinic. The study comprised of 232 women undergoing a total of 353 IVF cycles between 2007 and 2013 (17).
After researchers adjusted for age and calorie differences among the women, scientists discovered a positive correlation between total dairy food consumption and live birth rates among women aged 35 or older. Interestingly, while the women consumed both low-fat and full-fat dairy products, researchers discovered that the positive correlation was even stronger among those who consumed the higher fat versions of dairy foods (17).
Which dairy is best and how much should you be eating?
As you can see so far, the majority of studies which investigated the influence of dairy on women with PCOS used only low-fat or fat-free dairy products.
Comparative studies between whole milk, low-fat dairy and full-fat dairy have revealed that higher fat dairy products actually have lower levels of androgens such as testosterone and DHEA, while showing increased oestrogen and progesterone concentrations (18,19). This distinction is important, as oestrogen has been shown to decrease levels of insulin-growth factor-1 (IGF-1) in the body, which could contribute to more stable blood sugar levels (20).
Another study highlighted that both skimmed milk and full-fat milk had a 3-6-fold increase in their glycaemic response (21). However, the highest fat versions of dairy such as cheese have been shown to affect the insulin response to a lesser extent (22).
While there are still no formal guidelines as to whether dairy, or even how much dairy, should be consumed as part of a PCOS or fertility diet, it is advised that women with PCOS keep their dairy intake to 1-2 servings per day and focus on the full-fat versions instead (11).
One serving of dairy amounts to:
- 1.5 oz of hard cheese
- 1 cup of yogurt (choose an unsweetened variety)
Furthermore, it is also advised that you stick to organically grown dairy sources to reduce your exposure to chemicals, hormones and pesticides, often used in conventional farming (23).
How to get calcium and vitamin D without taking dairy?
One thing that you might be wondering if you’re looking to decrease your dairy intake is where you can get your calcium and vitamin D from.
It is very important to ensure that you are receiving adequate sources of calcium and vitamin D elsewhere – as dairy has traditionally been the main source of these vital nutrients for most women.
Calcium is necessary for the support of strong teeth and bones (24); while also playing a role in maintenance of healthy blood sugar, prevention of insulin resistance and support of foetal development during pregnancy (25,26). Experts suggest that the average adult should be consuming approximately 1,000mg of calcium per day (27).
Our top dairy-free calcium recommendations:
- White beans (191mg per cup = 19% RDA)
- Canned salmon (232mg per ½ can = 23% RDA)
- Sardines (321mg per 7 fillets = 32% RDA)
- Dried figs (107mg in 8 dried figs = 10% RDA)
- Bok Choy (74mg in 1 cup = 7% RDA)
- Kale (188mg in 2 cups raw = 19% RDA)
- Black-eyed peas (185mg in ½ cup = 18% RDA)
- Blackstrap Molasses (172mg in 1 tbsp = 17% RDA)
- Almonds (72mg in ¼ cup dry roasted = 7% RDA)
Vitamin D can be a little bit more challenging to find through a dairy-free diet and so, the simplest (and most fun!) recommendation is to aim for 15-20 minutes of direct sunlight daily - just make sure to be careful and protect yourself against burning. The daily recommended dose is between 400-800IU/day (27).
Our top dairy-free vitamin D recommendations:
- Wild-caught salmon (425IU in 3oz)
- Wild-caught mackerel (547IU in 3oz)
- Beef liver (42IU in 3oz)
- Egg yolks (41IU per yolk)
- Canned sardines (270IU in 3.5oz)
- Shitake mushrooms (40IU in 1 cup)
- Fortified almond milk (100IU in 8oz)
The bottom Line
Realistically, much more research is required before we can definitively identify the role of dairy in a PCOS and fertility diet. In particular, higher quality studies are needed, to more confidently decipher the true value (or not) of dairy in our diets.
In the meantime, if you suffer with acne or suspect an intolerance to dairy, it may be worth your while trying an elimination diet for a few weeks to see how you feel. To do this, simply remove all sources of dairy from your diet for 2 weeks and slowly reintroduce dairy products thereafter, paying close attention to your symptoms and how your body feels.
With that being said, if you don’t suffer from these symptoms then there is no reason why you shouldn’t include a moderate amount of full-fat dairy foods into your diet. After all, these foods provide a great source of calcium and vitamin D – two vital nutrients for fertility and a healthy pregnancy. Just make sure that you are choosing full-fat dairy to maximize the benficial outcomes and minimize potential negatives!
Did you know the differences between low and full-fat dairy?
Have you ever cut back on dairy because of hormonal issues or PCOS?
Head on over to our community forum and let us know!
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