The basic diet for pregnancy

The period before you are born is perhaps the most crucial time in your life to obtain optimal nutrition. During that period as a foetus you are responding to signals from your mother about the outside world. For instance, if your mother is not eating very much your body adapts to be able to cope better with food shortages. In fact the environment you encounter as a foetus in the womb, has an enormous effect on your risk of degenerative diseases, such as heart disease, diabetes and kidney disease in later life.

The basic diet for pregnancy

The optimal diet for the mum and foetus is one that we evolved with. That is one including meat, fish, eggs, nuts, seeds, fresh vegetables, fruit and honey. At the same time we want to avoid processed foods, (foods containing altered fats such as margarine) and limit starchy carbohydrates, especially those containing gluten such as bread.

 Foods to avoid

  • Processed foods, especially those with artificial sweeteners such as aspartame.
  • Mould ripened cheese may harbour listeria.
  • Uncooked eggs may harbour salmonella.
  • Pate can contain listeria.
  • Vitamin A in excess may harm your baby, therefore eat liver and pate only once per week.

Oily fish are identified as a source of toxins such as mercury, dioxins and PCBs by many health authorities. The official advice from the National Health Service in the UK is to limit yourself to two portions of oily fish per week. However, oily fish are the best source of omega 3 oils such as DHA, which is used to form much of the brain. So should you avoid oily fish such as salmon, trout, sardines, kippers, mackerel and tuna steaks?

  • The evidence against oily fish is variable. Mercury becomes toxic when it has deactivated selenium containing enzymes in the brain. If you consume enough selenium, then mercury in fish is not a big concern. In fact, only a few fish actually contain more mercury than selenium. The main examples being shark, whale, king mackerel, swordfish and marlin.
  • Dioxins and PCBs may still be present in oily fish, although levels are generally falling across the globe due to phasing out of manufacture due to concerns about their known toxicity. I personally recommend 3-5 portions of oily fish per week to my pregnant clients if they are not taking an omega-3 oil supplement. I also check to ensure they are likely to be getting enough selenium in their diet.

 How much carbohydrate, fat and protein

Breast milk in caloric terms is roughly 40% carbohydrate, 7% protein and 54% fat. This reflects the fact that an infant needs plenty of fat to help form the brain and plenty of carbohydrate to power the brain. Perhaps surprisingly not much protein is needed at this stage, but that is because in the first few months of life the brain is reaching full size. The proteins are needed later (from 6 months onwards), when the skeleton and muscular system grow from baby size to full adult size.

What this means for pregnancy is that a high fat diet is important. The important factor is to ensure that the fats you consume are healthy ones including plenty of omega 3 oils, the type available from oily fish. If you are vegetarian I recommend an omega 3 supplement, if not a fish derived one then one based on algae.

Weight gain during pregnancy

Anywhere between 5-18kg should be healthy and enough to nourish the foetus.

How much weight you put on should depend on your weight to start with. If you are obese then a smaller weight gain of between 5-9kg may be appropriate, whereas if you are underweight then weight gain of between 12-18kg would be best for the health of mother and baby.

If you are having twins then you can expect to add on another 50% of the weight gain expected for a single birth.

Example healthy weight gains for somebody of normal weight.

  • Single Birth: 14kg
  • Twins: 21kg

Gestational diabetes

This is experienced in up to 5% of pregnancies. It is caused by a diet that is too high in easily absorbable carbohydrates, when the mother has a pancreas that can’t produce enough insulin to buffer high levels of blood glucose.

The key nutritional change to make if you have diabetes diagnosed either before or during pregnancy, is to adopt a low GI diet, including:

  • meats, fish, eggs and dairy
  • vegetables other than potato
  • nuts and seeds
  • low GI carbohydrate sources such as lentils and porridge oats.

Pre-eclampsia (hypertension)

Pre-eclampsia is a condition which affects around 5% of pregnancies in the UK. It is thought to be due to problems with the maternal blood supply to the placenta early in the pregnancy, which then leads to a poorly developed placenta.

The key symptoms of pre-eclampsia are high blood pressure (hypertension) and protein in the urine.

Treatment typically involves taking blood pressure medication and giving birth a few weeks earlier than normal, by either inducing labour or having a caesarian section.

While you may inherit the susceptibility to pre-eclampsia, there are some nutritional considerations that could help. Primarily having enough calcium in the diet. Studies on people with poor calcium status showed significant benefits in pre-eclampsia rates on taking calcium supplements. Calcium is available naturally from:

  • Dairy produce such as yoghurt, milk and cheese.
  • Fish such as sardine and salmon.
  • Vegetables such as leafy green vegetables and tofu.
  • Plenty of sunshine should help also, as vitamin D helps with calcium absorption from the gut.

Morning sickness

There is some thought that drops in blood sugar may cause some cases of morning sickness. In this case, try to have a small breakfast, and then a small snack about every 2-3 hours outside of main meals. Make sure the foods you eat are low GI, that is those that minimally disrupt your blood sugar. Protein and fat containing foods such as meat, fish, eggs, dairy, nuts and seeds are safe. Some other foods containing primarily carbohydrate are also safe if they are slowly absorbed from the digestive tract. These include most vegetables except potatoes, lentils, peas and beans.

Some people find acupressure or full blown acupuncture to be helpful. There are some points just above the wrist that you can press on that can relieve morning sickness. Type in "acupressure point P6" into Google to see the general area. Consult an acupuncture practitioner to get full advice on this approach.

Postnatal depression - PND

There is some evidence that supplementation with selenium can help with post natal depression. In one study it was found that selenium supplementation of 100ug over the period of a pregnancy had a significant effect on measures of depression via the Edinburgh postnatal depression score questionnaire.

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

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Milton Keynes, Buckinghamshire, MK16
Written by Robin Dowswell, BSc MFNTP
Milton Keynes, Buckinghamshire, MK16

Robin Dowswell is a Nutritional Therapist working just outside Milton Keynes in Buckinghamshire. He specialises in sports nutrition, as well as having a keen interest in using diet as a powerful tool to enjoy improved health.

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