its levels are high, women show greater verbal fluency.
11 When its levels are low, women use their hands more skilfully, and spatial ability is stronger.
12 Excess oestrogen may increase the level of antithrombin III, which increases the risk of blood clots.
13 Normal levels in the follicular phase are 30–150ng/ml. In menopause, oestrogen levels are 40–200ng/ml.
Progesterone, on the other hand, has different roles from oestrogen:
1 Stimulate the endometrium to become nutrient-rich in preparation for a pregnancy, from day 14 to 28 of the cycle.
2 Enhance relaxation of the uterus and prevent contractions of the uterine smooth muscle to prevent miscarriages.
3 Inhibit oestrogen from stimulating contractions of the uterus, maintain a pregnancy and prevent further ovulation.
4 Reduce the effect of the immune system to prevent the body from rejecting the embryo.
5 Raise the basal metabolic rate.
6 As a thermogenic, adjust body temperature, which rises from 97.8 degrees C to 98.3 degrees C just before ovulation.
7 It is synthesized from cholesterol in the corpus luteum and in the placenta from months three to nine during pregnancy.
8 Normal levels of progesterone are greater than 10ng/ml during the mid- to late luteal cycle.
Figure 2.2
Diagram of the endocrine (hormone) relationships between the anterior pituitary and ovary. The pituitary secretes FSH (follicle-stimulating hormone) to stimulate the growth of the follicle which contains the egg. When the egg is ripe and the follicle large, the pituitary secretes LH (luteinizing hormone) and the egg is expelled (ovulated). After ovulation, the follicle becomes the corpus luteum. The follicle produces oestrogen and the corpus luteum progesterone [(+) means stimulates and (-) means inhibits].
The follicle granulosa cells produce oestrogen from day 1 to day 14 of the cycle; then the corpus luteum produces progesterone from day 15 to day 28 of the cycle. As these steroid hormones are both oil-based, the health of these hormones depends upon the quality of the oils you eat. Both are synthesized from cholesterol.
Androgens play a role in fertility:
1 They are precursors to oestrogen and come from the ovary and adrenal glands.
2 Testosterone is the male hormone produced in the testes, ovaries and adrenals. In women, excess may be produced if insulin levels are too high.
3 In women, testosterone levels are normally 35–50ng/ml. It is felt that there is a slight surge at the time of ovulation that increases the sex drive.
OVARIAN CYSTS
Often, women with endometriosis develop cysts on the ovaries. There are four main types of cyst:
1 Dermatoid cysts are rather bizarre and contain tissue that has developed into hair, nails and teeth. They are unusual.
2 Mucoid cysts are filled with a clear mucus and may grow to be very large.
3 Endometrial, or ‘chocolate’, cysts are related to endometriosis and appear to be unruptured follicles that fill with blood and become larger and larger. Size is usually given in terms of a fruit (tangerine-sized to grapefruit-sized), or up to the size of a five-month-old fetus in one case.
4 Polycystic ovaries, where six or more small cysts develop at the same time (see chapter 3).
The ovary is able to reabsorb cyst material and research suggests that a diet rich in B-complex vitamins aids this process. Cysts may grow within the ovary but, more often, they are attached to the ovary by a stalk. Pain ensues when this stalk becomes twisted or the ovary ruptures, spurting out hot stale, sticky blood onto the intestines. This pain is unbearable as the whole of the bowel muscles go into spasm and the body goes into shock. It is known that some cysts produce their own hormones, upsetting the hormonal balance. Small cysts can be reabsorbed, but those over 5cm in diameter are best removed surgically with a laser.
Figure 2.3
Cross-section of the uterus and Fallopian tube, and diagrams of the development of the egg to embryo. (A) Fertilization of ovum. (B) Fertilized egg with pronuclei. (C) Two-cell embryo. (D) Four-cell embryo. (E) Multicellular embryo (100 cells) – a morula. (F) Early blastocyst embryo. (G) Blastocyst invading the endometrium.
THE UTERUS
The uterus or womb is a little smaller than a woman’s clenched fist, but during pregnancy, it can expand to over 45cm (18in) in length (see figures 2.1 and 2.3). It consists of a well-developed muscular wall (the myometrium) and an inner mucus-like membrane (the endometrium). The smooth muscle wall of the myometrium expel the baby during the birthing process, and it is the contractions of these muscles that also cause menstrual cramps. These muscles require a balance of calcium and magnesium to help them function correctly. Calcium tenses muscles while magnesium allows them to relax. Magnesium-rich foods should be eaten when muscular cramps are a problem.
The uterus retains its full capacity to sustain implantation for up to 60 years of age. It clearly does not age in the same way as the ovary, as postmenopausal women can maintain a pregnancy after egg donation. ‘The uterus is the main site for the production of the hormone prostacyclin, which protects women from heart disease and unwanted blood clotting. Since prostacyclin cannot be synthetically made in a laboratory, the removal of the uterus will ensure its production will cease forever.’5 It also produces 60 different prostaglandins and enzymes.
THE ENDOMETRIUM
The endometrium (tissue lining the womb) plays a vital role in the reproductive process (see figures 2.3 and 2.4). The endometrium is brownish-red in colour with a fluffy appearance and slimy texture. The brownish-red colour is due to its nutrient-rich blood supply, and the slimy texture is due to the large amount of protein contained in its secretions. For a woman to conceive, the embryo must physically implant into this ‘lush’ endometrium. The endometrium is the sole source of nutrients and oxygen for the newly formed embryo. If nutrients are in poor supply, the womb lining will be unable to support the embryo’s development. The growth of the embryo places a heavy nutrient demand on the endometrium, and this tissue needs to develop a rich blood supply. As we will see later, the quality of food eaten greatly influences the nutrients available to the endometrium. Pregnancy is rare if the endometrium thickness is less than 7mm. The chances of pregnancy are optimized if the endometrium is 9–14mm in thickness.6
The endometrium is also an important endocrine gland and secretes a family of hormones called prostaglandins (PG). Prostaglandin F (PGF) can stimulate strong uterine contractions (cramps) and prostaglandin E (PGE) can cause pain. These prostaglandins are the hormones directly responsible for most of the cramps and pain associated with endometriosis and menstruation. PGF also inhibits the development of the corpus luteum in the ovary and therefore reduces progesterone production. Therefore PGF has been used clinically to initiate abortions. If higher levels than normal of PGF are produced, miscarriages may occur.
As an endocrine gland, the endometrium is very responsive to the levels of hormones circulating in the blood. The balance of oestrogen and progesterone greatly affects the growth and activity of the endometrium. In chapter 11, the effects on the balance of what you eat will be clearly explained.
FALLOPIAN TUBES
The womb has two tube-like extensions called the oviducts or