Good nutrition is essential if you're thinking about starting a family or trying to conceive. Find out which foods are packed with the nutrients you need, and which foods you should be steering clear of.

1. Get your minerals and vitamins
"Two things that are really important are vitamin C and zinc," says dietician Sian Porter. "You want to eat plenty of foods containing zinc - so things like seeds, nuts, shellfish, and wholegrain cereals. Include plenty of fruit and vegetables in your diet, particularly citrus fruits for vitamin C."

"Zinc is probably the most important fertility nutrient," says nutritionist Penny Crowther. "It is responsible for hundreds of enzyme systems, many of which affect sexual performance and fertility. After fertilisation has occurred - whether naturally or in a test tube - the embryo cells need to divide and grow and zinc is absolutely vital for this process. Zinc deficiency can increase the risk of miscarriage and low birth weight babies."

Men should also pay attention to their nutrition when planning a family. "Vitamin E when combined with selenium is particularly effective at improving sperm motility and quality," says Penny Crowther.

Sources of zinc: meat, shellfish, milk, cheese, bread, and wheatgerm
Sources of vitamin C: citrus fruits and dark green, leafy vegetables
Sources of vitamin E: egg yolks, nuts, cold pressed oils, avocados, and green leafy vegetables

For information on vitamin and mineral intakes prior to and during pregnancy, visit the Food Standard Agency's healthy eating site.

2. Watch your weight
"It's crucial for women to obtain an optimum level of body fat (at least 18 per cent)," says Sian Porter, dietician and member of The Fat Panel (an independent UK body of GPs, nutritionists and lipidologists).

"If the level drops below this, it can lead to hormone imbalances, which may result in a failure to ovulate. At the other extreme, obesity can lower a woman's chance of conception."

3. Eat the right fats
"Fats are really important in your diet, as they carry fat soluble vitamins," says Sian Porter. Avoid trans fats, also known as hydrogenated fats, which are found in many processed foods, and make sure you include good fats - which contain essential fatty acids - in your diet.

Sources of good fats: oily fish, nuts, seeds, avocados, olive oil spreads and vegetable oils

4. Avoid alcohol
"Drinking too much alcohol can interfere with your body's uptake of B vitamins and certain minerals," says Sian Porter. Whilst you're trying to conceive, it's best to stop drinking completely. If you do drink during this time, limit yourself to 1-2 units per week.

5. Avoid extreme diets
Don't follow radical diets which require you to exclude whole food groups. By excluding groups such as carbohydrates, you can run the risk of lowering your intake of vitamin B and other important nutrients.

6. Avoid processed foods
It's a good idea to eat a balanced diet throughout your life, but it's particularly important to get the right nutrients when you're trying to conceive. Processed foods often contain trans fats, which can raise cholesterol levels and increase the risk of heart disease. Avoid processed foods, and aim to eat a well-balanced diet.