Fats from good healthy sources are an important part of your diet, particularly if you are trying to conceive. They help in the manufacturing of hormones and in regulating ovulation. So, whilst it’s important to eat a healthy, balanced diet to get fit for fertility, it is also important to eat fats for fertility.
Research about the possible benefits and harmful effects of dietary fat is always evolving and changing the way experts think. There has been much debate over the years as to whether reducing our fat intake and following a low fat diet is healthier than a diet that contains a higher amount of fat such as saturated fat. There is still further research needed to clarify exactly how much saturated fat is actually needed by the body to remain ‘healthy’, but it is also important to acknowledge that the human body needs fat to function effectively and that everyone is different (biochemical individuality) and so different people will need different amounts of saturated fat dependant on age, sex, and activity levels etc. There are also different types of fat, which does complicate the issue!
A growing body of research is indicating that when it comes to dietary fat, the focus should be on eating more of the ‘healthy’ fats such as omega 3 fatty acids along with monounsaturated and polyunsaturated fats (as well as some saturated fat) and less of other, not so ‘healthy’ fats such as the trans fats. Remember, we all need a certain amount of fat in our diet in order to function.
Fat is important in our diet for a variety of reasons including:
- Healthy skin
- Cell membranes
- Absorption of fat soluble vitamins (A,D,E and K)
- To provide the essential fatty acids – Linoleic and Linolenic acid (the body cannot make these itself or work without them).
- Brain development
- Control of inflammation
- Blood clotting
- Production of oestrogen and other hormones
Types of fats
This is a type of fat that comes mainly from animal sources of food, such as red meat, poultry and full-fat dairy products.
Trans fats are liquid oils that have been turned into solids by a process called hydrogenation and are in thousands of pre-prepared foods to give texture and a long shelf life.
Examples of some popular foods that may contain trans fats – check the food label for any hydrogenated fats:
- French fries/some chips
- Pastries, pies
- Most things that have been battered or fried
- Cake mixes
- Some ice creams
- Frozen microwave meals
Monounsaturated fatty acids
This is a type of fat found in a variety of foods and oils such as olive oil, avocados and nuts such as Brazil nuts. Studies show that eating foods rich in monounsaturated fatty acids improves blood cholesterol levels, which can decrease your risk of heart disease. Research also shows that these fatty acids may benefit insulin levels and blood sugar control, which can be especially helpful if you have type 2 diabetes.
Polyunsaturated fatty acids
This is a type of fat found mostly in plant-based foods and oils found in some fish and oil, such as sunflower oil. Evidence shows that eating foods rich in polyunsaturated fatty acids improves blood cholesterol levels, which can decrease your risk of heart disease. These fatty acids may also help decrease the risk of type 2 diabetes.
Omega 3 fatty acids
One type of polyunsaturated fat is made up of mainly omega-3 fatty acids and may be especially beneficial to your heart. Omega-3, found in some types of fatty fish, appears to decrease the risk of coronary artery disease and also helps reduce inflammation in the body.
Fats and fertility
There has been research carried out which has indicated that consuming fat is important when it comes to fertility – but it must be the right fat, and the right amount!
Body fat cells produce oestrogen which is needed to maintain cholesterol levels, healthy bone formation, gene expression, and to regulate the menstrual cycle. Research has indicated that there is a balance to be had as consuming too much fat can lead to obesity and this can lead to fertility problems. Conversely women who have a low BMI (or not an adequate amount of body fat) may not be ovulating and have irregularities in the menstrual cycle.
Consumption of trans fats can lead to obesity which may impact on fertility by affecting ovulation, increasing insulin resistance and by increasing inflammation. Trans fats seem to amplify the symptoms of PCOS (Poly Cystic Ovary Syndrome) and may cause endometriosis in some women.
Researchers from Harvard Medical School investigated 18,800 women and looked at the effect of trans fats on fertility. They discovered that a consumption of 2% trans fats in the diet doubled the risk of infertility (Chavarro et al 2007). The study also looked at the effects of high and low fat dairy on female fertility. It found that an increase of just one serving of low-fat dairy food per day was associated with an 11% greater risk of infertility.
It was also discovered from this research that eating high fat dairy was associated with a reduction of the risk of infertility. For instance, it was found that the addition of one serving of whole fat milk per day was associated with a 50% drop in infertility risk. Increased intake of calcium and vitamin D were also associated with a lower risk – full fat dairy products are more likely to contain these substances.
Researchers concluded that the negative impact of low fat dairy on fertility was likely to be a result of IGF-1 levels. Studies have shown that milk consumption can increase IGF-1 levels (which can negatively affect fertility) and it is believed that low fat milk in particular might drive this association.
The research team also concluded that the association between the consumption of high fat dairy and improved fertility has a couple of likely explanations.
High fat dairy products have more oestrogen than their low-fat counterparts, and oestrogens decrease IGF-1 levels (and so improve fertility). There is also evidence that high fat dairy products may improve insulin sensitivity. Further research is still needed on this topic to validate its conclusion.
Some top nutrition tips for fats and fertility
- Eat organic, free range eggs as they are an excellent source of vitamins A, D, and E, along with EPA (eicosapentaenoic acid), DHA (docosahexaenoic acid) and choline.
- Include 2-3 portions of oily fish into your diet each week, such as wild salmon, mackerel, sardines and herring. These foods contain essential fatty acids which can be improve female fertility due to their anti-inflammatory properties. Fish oil is also highly beneficial for maintaining a healthy pregnancy and the DHA found in fish oil is crucial to building your baby’s brain.
- Substitute coconut oil for cooking as it can withstand high heat without oxidizing. Coconut oil also contains lauric acid which provides anti-viral properties, and is metabolized quickly for energy.
- Other healthy foods that contain fat choices that are beneficial to fertility, pregnancy and overall health include nuts, seeds, avocado, and flax seed/flax oil.
- Research is now leaning towards the fact that we should all include some saturated fat in our diet, but further studies are being carried out into exactly how much is to be recommended. Good sources are butter, full fat milk, cream and red meat.
Chavarro, J., Rich-Edwards, J., Rosner, B. and Willett, W. (2007) Dietary fatty acid intakes and the risk of ovulatory infertility. American Journal of Clinical Nutrition, Vol. 85, No. 1, pp231-237.
Missimer, S. et al.,(2010) Trans fats linked to increased endometriosis risk and omega-3-rich food linked to lower risk. European Society of Human Reproduction and Embryology. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2873173/
A prospective study of dairy foods intake and anovulatory infertility. Chavarro JE1, Rich-Edwards JW, Rosner B, Willett WC. http://www.ncbi.nlm.nih.gov/pubmed/17329264/