Dr Charmaine Ma, BSc(Pharm), MD, Dip Fam Med (HK), CCFP
In today’s multimedia age, coupled with endless food choices and specific meal plans, it is often difficult to differentiate what type of diet we should have in order to stay healthy. If you’ve tried typing in ‘diet and X’ (X can be anything from fertility to finding a date) into a search engine, you’ll be bombarded by advice on how specific diets can lead to desired outcomes. We will have a look at some basics on diet and how it may affect fertility.
What is a healthy weight
You may have heard it time and time again- the most common way to calculate healthy weight is through the body mass index (BMI). BMI is calculated through taking a person’s height (in kg) and dividing it by their height (in meters) squared. The formula is BMI=kg/m2. The normal range of BMI is between 18.5-24.9 for both men and women.
This ‘magic number’ is an estimate of the amount of body fat compared to height and may differ depending on your body composition, ethnicity, age or activity level. It is used as a gauge but cannot determine your health based on other factors (such as blood pressure, blood sugar or cholesterol). A conversation with your family doctor would be useful if you have any questions.
Supplements, Diet and Fertility
A recent article from Harvard reviewed the effects of diet and fertility. The basic take-away points I concluded from the review include:
Women trying to conceive without assisted technologies (such as IVF) may benefit from folic acid, Vitamin B12, omega-3 fatty acids and healthy diets (such as the Mediterranean diet).
Vitamin D (when not deficient originally), dairy and soy products, caffeine, alcohol and antioxidants didn’t seem to have any positive or negative effects
Trans fats and diets high in red or processed meats, sweetened beverages, sugars and potatoes had negative effects
Men had improved semen quality with healthy diets, seem unaffected by alcohol and caffeine and had negative effects from trans fat and processed diets.
The conclusions from this review are similar to those that I had written about in our Natural Medicines series and focus should be put on the fact that even though some products do not seem to have any positive or negative effects currently we should be skipping or overindulging in them (e.g. caffeine or alcohol).
Mediterranean Diet and Pregnancy Outcomes
Along the same lines of diet and fertility a recent trial in the UK looked at the pregnancy outcomes of over 1200 pregnant women based on whether they followed a ‘Mediterranean’ diet (higher in nuts, olive oil, fish, non-refined grains and vegetables) versus a more ‘traditional’ diet (higher in sugary drinks, fast food, animal fats).
The general outcome of the study showed no significant change in outcomes of mom or baby but did see a reduction in risk of gestational diabetes (which can lead to larger babies and poorer outcomes). This may be due to less weight gain in the Mediterranean group compared to the traditional group.
The overall takeaway message I gained from this study is that, as many studies are now showing, a diet that avoids processed, sugary or animal fats is generally more healthy. I think this is a good rule-of-thumb even for the general public and would lead to better health when coupled with appropriate exercise.
Next steps for researchers would be to observe whether diets during pregnancy can affect childhood outcomes such as obesity, allergy or asthma. Stay tuned!
Al Wattar BH, Dodds J. et al. Mediterranean-style diet in pregnant women with metabolic risk factors (ESTEEM): A pragmatic multicentre randomised trial, PLOS Medicine (2019). DOI: 10.1371/journal.pmed.1002857
Dr. Charmaine Ma, BSc(Pharm), MD, Dip Fam Med (HK), CCFP