woman’s reproductive life means that her nutritional needs differ greatly from those of a man. Menstruation, pregnancy, breastfeeding and menopause are times of increased nutritional demand.

With the popularity of crash dieting, nutritional deficiencies are common, especially among young women. Good nutrition means eating a wide variety of foods every day, which isn’t possible on a restrictive diet.


The interplay of hormones throughout a woman’s menstrual cycle affects her body and state of mind. Energy intakes are generally higher in the premenstrual phase and some women also have food cravings as their period approaches. Eating high protein foods every few hours can often temper or stop the cravings. This should not be done at the expense of other food groups, especially carbohydrates, which should form the basis of the diet.

Fluid retention is common in the days leading up to a period because certain hormones encourage the body to hold salt (sodium). The more sodium the body holds, the more fluid is retained in the tissues.

Other common symptoms of premenstrual syndrome (PMS) include moodiness, tiredness and constipation. There is some evidence that taking B-group vitamins, particularly vitamin B6, can help. Light to moderate exercise, such as a 30-minute brisk walk each day, has also been shown to noticeably reduce symptoms of PMS.


Iron is a mineral that works with other substances to create haemoglobin, the compound that carries oxygen in the blood. Women and men metabolise iron from food at roughly the same rate. However, while men need around 8mg of iron in their daily diet, women need up to 18mg (or 27mg if pregnant). This is to make up for the amount of iron they lose in their menstrual period, which averages around 1mg or so lost for every day of bleeding.

Iron deficiency is the most common nutrient deficiency in women. Insufficient iron can lead to anaemia. Common symptoms include tiredness and breathlessness. Iron deficiency in pregnant women increases the risk of having a premature or low birth weight baby, which can have a negative impact on the short and long-term health of the baby.

• Red meat
• Fortified cereals
• Egg yolks
• Legumes and nuts
• Leafy green vegetables.
• Iron absorption can be impaired by very high fibre diets, alcohol and the tannic acid in tea.

The extraordinary demands on the female body during pregnancy can lead to nutritional deficiencies if the mother does not alter her diet. Pregnant women only need 600kJ or 140 kilocalories (kcal) more than non-pregnant women, which can be easily achieved by eating a little more from each of the five food groups daily.

The most common deficiencies in pregnant women include:

• Calcium – although a developing baby needs a lot of calcium, which is taken from the mother’s bones, most women rapidly replace this bone loss once the baby has stopped breastfeeding. The woman should make sure she has enough calcium in her diet during pregnancy, as this may protect her bone mass while also meeting the needs of the foetus. Good sources of calcium include dairy products (milk, cheese and yoghurt).
• Folic acid (folate) – the recommended daily intake (RDI) for folic acid increases dramatically during pregnancy. Folic acid is needed for the development and growth of new cells. Research suggests that insufficient folic acid at conception and in the first trimester of pregnancy can increase the risk of neural tube defects in the unborn baby. Good sources of folic acid include leafy green vegetables, poultry, eggs and cereals, particularly fortified cereals.
• Iron – the developing foetus draws enough iron to last through the first five or six months after birth. Iron supplements are frequently prescribed for pregnant women, especially during the third trimester. These should only be taken on medical advice, as iron is toxic in large amounts and can be fatal at high doses. Iron-rich foods include red meat, egg yolks and leafy green vegetables.
• Zinc – zinc is needed to maintain the health of cells. Taking iron supplements may interfere with the absorption of zinc, so women taking iron supplements may also need zinc supplements. Foods high in zinc include meat, eggs and seafood. Leavened wholegrain products can also be helpful (yeast helps release the bound zinc).

Nutrient requirements generally increase a lot more during breastfeeding (500–800kcal) than in pregnancy (140kcal). Important nutrients during this time are protein, calcium, vitamin C, folate, zinc, magnesium, vitamin B6 and fluids. Women who have not accumulated sufficient iron stores during pregnancy can develop iron deficiency anaemia when they are breastfeeding. This can be addressed by increasing the amounts of iron-rich foods eaten every day or, if necessary, taking supplements if advised to do so by your doctor.


Osteoporosis is a disorder characterised by a thinning of the bones until they are weak and easily fracture or break. Women are at greater risk of developing osteoporosis than men, particularly after menopause, because oestrogen levels are reduced. There are many factors involved, for example:

• Low calcium intake during the growing years – this increases the susceptibility to osteoporosis later in life. Bone strength in later life depends on the development of bones earlier in life. Adequate calcium intake during youth is essential to achieve peak bone mass.
• Diet – salt, caffeine and alcohol interfere with the balance of calcium in the body because they increase the amount lost in the urine. Consume them sparingly.
• Exercise – or the lack of it, can also affect the development of osteoporosis.
• Low body weight – maintaining a low body weight (body mass index less than 18) has been associated with the development of osteoporosis.

Vitamin D increases calcium absorption and is required for normal bone metabolism. The main source of vitamin D for most people is sunshine. Good dietary sources are margarine, eggs and fatty fish from the northern hemisphere such as mackerel and sardines.

Good sources of calcium include dairy foods, calcium-fortified soymilk and sesame seeds. However, for women who can’t eat these foods, calcium supplements may be desirable.


Phytoestrogens have been linked to a range of health benefits, especially for women. They are natural substances found in certain plant foods including:

• Whole grains including cracked wheat and barley
• Flaxseed (linseed)
• Sesame seeds
• Nuts including almonds
• Legumes especially soy and chickpeas
• Alfalfa sprouts
• Herb teas especially sage and aniseed
• Extra virgin olive oil.
• Oestrogen and phytoestrogens
• Phytoestrogens are natural oestrogen-like substances. Oestrogen is a hormone that is necessary for optimal health. There is a link between oestrogen levels and the development of heart disease, cancer and osteoporosis. At present there is no evidence that increasing the intake of phytoestrogen will prevent heart disease, cancer and osteoporosis.

• Iron and calcium deficiencies are common in women.
• Vitamin B6 can help ease the symptoms of premenstrual syndrome.
• Large quantities of foods like tea, alcohol, caffeine and salt can interfere with the absorption and excretion of important minerals.