Women's Health // 4 Important Micronutrients

This post has been adapted slightly from one that I wrote a few months ago for Glow Gathering. As women, it is important to remember that many of our needs can differ from our male counterparts. Central to these needs is our unique hormonal and metabolic makeup, including our menstrual cycle, and our ability to fall pregnant, nourish a growing foetus, and eventually give birth. When we consume a diverse range of different nutrient-rich foods in our diet, we will generally be able to provide our bodies with the nutrients that we need for daily energy and important bodily processes, but I thought that I'd highlight just a few important micronutrients that us as women should prioritise for reasons that will be described in the post below.


Folic Acid / Folate

Folate and folic acid both refer to a B vitamin that is critical for red blood cell production, DNA formation during cell replication, and nerve function. Folate is the form found naturally in food, whilst folic acid is the synthetic form that is commonly found in supplements and fortified foods. Folate is particularly important in the first trimester of pregnancy as it is during these first few weeks where a foetus experiences rapid spinal cord and nerve cell development (remember that this is often the time when a woman doesn’t even know that she is pregnant). When a pregnant mother has insufficient folate stores and daily intake, it can affect the DNA synthesis and cell replication in a growing foetus, which can result in birth defects such as Spina Bifida.

This is why many public health guidelines recommend that women of childbearing should consume sufficient folate-rich foods to meet the RNI of 200µg/day, and that women who are considering pregnancy or are pregnant (particularly during the first trimester) should take a 400µg folic acid supplement in addition to consuming folate-rich foods.

 
Folic acid

Folic acid

 

 

What foods contain folate?

It is important to remember that although folate is widely found in the foods listed below, it is often lost through cooking. A good way to preserve the folate found in your vegetables is to lightly steam them where possible or consume them raw.

  • Green leafy & cruciferous vegetables (spinach, kale, Brussels sprouts, cabbage, and broccoli)

  • Asparagus

  • Beans & legumes

  • Wheat bran & whole grains

  • Meat, fish & poultry

  • Folate-fortified foods (wheat flour and products made using wheat flour in some countries)

 

Iron

Iron is essential for the production of haemoglobin and healthy red blood cells, which are needed for oxygen transport throughout our body. Iron deficiency is one of the most common nutritional deficiencies worldwide, and is particularly prevalent in women due to the monthly iron losses we experience through menstruation. Iron deficiency can lead to symptoms such as:

  • Exhaustion

  • Fatigue

  • Dizziness

  • An irregular heartbeat

  • Shortness of breath

  • Weakness

This is due to the fact that when a person is iron deficient, less oxygen is able to reach their tissues where it is needed for energy production and cell metabolism. Iron also has an important role to play in maintaining a healthy immune system, and thus mild iron deficiency can often result in a higher susceptibility to infections. Interestingly enough, although iron needs increase during pregnancy, a woman's body adapts through the combination of no menstruation and increased efficiency of iron absorption so that a pregnant mother with optimal iron stores prior to falling pregnant does not usually need to actively increase her iron intake during pregnancy. Cool hey?

What foods contain iron?

Iron can be found in either the haem or non-haem form in foods:

  • Haem iron is present in animal sources such as red meat, poultry and eggs, and is very well absorbed by the body

  • Non-haem iron can be found in plant foods such as legumes, dark green leafy vegetables, tofu, nuts, seeds, and fortified cereals

Although non-haem iron is not absorbed as well as haem iron, vegetarians and vegans should be able to meet their daily needs by consuming a variety of iron-rich plant foods in their diet including:

  • Chickpeas

  • Kidney beans

  • Dried apricots

  • Brazil nuts

  • Hazelnuts

  • Sesame seeds

  • Tofu

  • Green leafy vegetables

A top tip for optimising iron absorption is to consume vitamin C rich foods alongside iron-rich plant foods, because vitamin C helps to enhance iron absorption in the gut.

 

Vitamin D

Vitamin D has several important functions in the body. These include the:

  • Promotion of calcium absorption

  • Regulation of calcium and phosphate levels in the blood

  • Promotion of bone health and cell growth

  • Reduction in systemic inflammation

It is important to note that vitamin D is the only vitamin that our bodies are able to produce. When UVB rays of a specific wavelength hit our skin, vitamin D3 is produced from a steroid prohormone known as 7-dehydrocholesterol, which means that basically when you spend time outdoors in the sun, your body is able to produce its own Vitamin D. However this means that individuals that live very far North or South are at a higher risk of developing vitamin D deficiency during certain times of the year, thus a daily 10µg vitamin D supplement is recommended during the Autumn and Winter months when UVB exposure is low. Vitamin D deficiency can occur as a result of dietary inadequacy, impaired absorption and use, increased needs, or increased excretion.

It is becoming evident that this vitamin has an important role to play in women’s health, particularly in the activity of reproductive hormones such as oestrogen and in the maintenance of bone strength after menopause. Most of us know that vitamin D is important for good bone health in women, however new research has also highlighted its importance in immune function, cell metabolism, as well as good pregnancy outcomes. Optimal vitamin D status is important in pregnancy because a developing foetus obtains all of the vitamin D that it needs for bone and immune system development from its mother. Babies that are born with low levels of vitamin D and infants that don’t obtain enough through breast milk or formula may develop rickets, which can cause permanent bone deformities and growth retardation. Poor vitamin D status in women increases their risk of developing osteomalacia (bone softening) and osteoporosis later in life.

What foods contain vitamin D?

  • Oily fish

  • Egg yolks

  • Fortified dairy, cereals and soy products

  • Mushrooms grown in the sun

  • Oysters

 

Iodine

This is probably the least well known of these micronutrients, however it is an important one as iodine is an essential component of our thyroid hormones T4 (thyroxine) and T3 (tri-iodothyronine). These hormones are critical for the regulation of our metabolism, breathing, heart rate, growth, temperature, and even digestion. When our iodine requirements are not met through dietary intake, our thyroid is unable to produce sufficient amounts of these hormones and we can end up experiencing exhaustion, an inability to concentrate, unexplained weight gain, and feeling really cold (even on hot days). Severe iodine deficiency can result in something known as goiter, which is an enlargement of the thyroid due to hypertrophy (cell growth) that happens as the thyroid tries to compensate for decreased iodine.

 
Thyroxine ( T4 )

Thyroxine (T4)

 
Triiodothyronine ( T3 ) 

Triiodothyronine (T3

 

During pregnancy, a mother’s thyroid hormones also have a direct effect on the brain development of a growing foetus. This is why ensuring adequate iodine status in women before and during pregnancy is one of the most important preventable cause of irreversible brain damage in infants. Although up to 20mg of iodine can be stored in our thyroid, we still require a daily intake through our diet. The WHO RNI for iodine is 150µg/day for adult women and 250µg/day for pregnant and lactating women.

 

WHAT FOODS CONTAIN IODINE?

  • Seaweed

  • Haddock

  • Cod

  • Salmon

  • Mackerel

  • Sardines

  • Iodised salt in countries such as South Africa

  • Milk 

The availability of iodine in foods differs between regions. Those living in countries such as South Africa and the United States can easily maintain adequate iodine intake through the consumption of iodised salt. In the U.K. on the other hand, the main dietary source of iodine is cow’s milk and dairy products due to the iodine-rich cattle feed. Most women following a healthy, balanced diet containing these foods should be able to meet their iodine needs with ease, and taking an iodine supplement without medical supervision is not recommended because excessive iodine intake can result in thyroid problems. 


Additional Resources

Glossary

  1. MACRONUTRIENTS - These are nutrients that we require in larger daily amounts (tens or hundreds of grams) to provide energy and support normal growth, health, and maintenance in our bodies. Carbohydrates, proteins, and fats are included in this group of nutrients.

  2. MICRONUTRIENTS - These are nutrients that we require in very small quantities in our diet (several milligrams or micrograms per day), but are critically important to the proper functioning of our brain, bones, and body. Vitamins and minerals are included in this group of nutrients.

  3. VITAMINS - A group of unique organic compounds that are required for normal growth, health, and metabolic integrity of our bodies. They are essential in our diet, as our bodies are unable to synthesise them.

  4. MINERALS - In contrast to vitamins, minerals are essential inorganic elements that have an important physiological function in the body. They are required in the diet in either macro (milligram) or trace (microgram) amounts.

  5. RECOMMENDED NUTRIENT INTAKE (RNI) - This is the amount of a nutrient that should be enough to ensure that the needs of nearly all of the population (97.5%) are being met.

 

Fact Sheets

  1. Folate - BDA fact sheet + Dietitians of Canada fact sheet

  2. Iron - BDA fact sheet + Dietitians of Canada fact sheet

  3. Vitamin D - BDA fact sheet + Dietitians of Canada fact sheet

  4. Iodine - BDA fact sheet + Dietitians of Canada fact sheet


References

[1] Introduction to Human Nutrition (Gibney et al.)

[2] Bernal, J. Thyroid hormones and brain development. Vitam Horm. 2005;71:95-122.

[3] Kapil U. Health Consequences of Iodine Deficiency. Sultan Qaboos Univ Med J. 2007 Dec;7(3):267-72.

[4] Khadilkar SS. The Emerging Role of Vitamin D3 in Women’s Health. J Obstet Gynaecol India. 2013 Jun;63(3):147-50. 

[5] American Thyroid Association – Iodine Deficiency

[6] Willing MC, Sowers M, Aron D, Clark MK, Burns T, Bunten C, Crutchfield M, D’Agostino D, Jannausch M. Bone Mineral Density and Its Change in White Women: Estrogen and Vitamin D Receptor Genotypes and Their Interaction. J Bone Miner Res. 1998;13:695-705.