When we read about Vitamin C deficiency, the word "thryoid? is almost
never seen. Likewise, when we read about the thyroid gland, Vitamin C
is almost never mentioned. There is a connection, albeit not a
prevalent one. Very few people in developed countries suffer from
Vitamin C deficiency, particularly since Vitamin C, also known as
ascorbic acid, is a common food preservative, making ?C? deficiency
The thyroid gland produces hormones that regulate protein,
carbohydrate, fat, and vitamin metabolism, along with generation of
body heat. Thyroid hormones also regulate the activity of the
autonomic nervous system. Hormone levels secreted by the thyroid are
controlled by the pituitary gland's thyroid-stimulating hormone(TSH),
which in turn is controlled by the hypothalamus.
The primary hormones produced by the thyroid gland are T3 and T4. T3
needs 3 atoms of iodine, and T4 needs 4 atoms of iodine to be
effective. Why are we talking about iodine? In order for iodine to be
utilized properly, it requires the presence of tyrosine, an amino acid
and precursor of thyroid hormones, as well as being necessary for
adrenaline and noradrenaline production. Vitamin C is necessary for
tyrosine metabolism, and it is quite a delicate balance!
?Stress is known to affect thyroid function. The amino acid tyrosine
is necessary for the production of steroid hormones adrenaline and
noradrenalin. When the body is under stress more of these hormones are
required and tyrosine reserves are depleted, leaving the thyroid
hormone pathway under functioning. Stress depletes many of the
essential nutrients required for thyroid function ? the B vitamins,
vitamin C, zinc and selenium especially.
Individuals who are stressed may therefore require additional adrenal
support in order to improve their thyroid function. There are many
nutrients and herbs, which can help support the adrenal glands.?
?The thyroid hormones travel through the bloodstream to every cell in
the body, where they keep everything working optimally, like oil in an
engine. Without enough thyroid hormone in its active state (T3), the
metabolism slows down, resulting in lowered pulse rate, coldness,
weight gain, and fatigue. Other body functions slow down as well?the
mind can't function normally, skin becomes dry and flaky, hair falls
out, muscles become cramped, and so on.?
?Vitamin C promotes healthy teeth and gums, helps in the absorption of
iron, aids in the maintenance of normal connective tissue, and
promotes wound healing. It also helps the body's immune system.?
Vitamin C does play a role in thyroid hormone production, according to
the University of Maryland Medical Center:
·Avoid foods that suppress thyroid function, including broccoli,
cabbage, brussels sprouts, cauliflower, kale, spinach, turnips,
soybeans, peanuts, linseed, pine nuts, millet, cassava, and mustard
·Avoid refined foods, dairy products, wheat, caffeine, and alcohol.
·Essential fatty acids (1,000 to 1,500 mg three times per day) are
necessary for hormone production.
·Vitamin C (1,000 mg three to four times per day), vitamin A (10,000
to 25,000 IU per day), B complex [(50 to 100 mg/day), augmented with
vitamins B2 (riboflavin, 15 mg), B3 (niacin, 25 to 50 mg), and B6
(pyridoxine, 25 to 50 mg)], selenium (200 mcg per day), iodine (300
mcg per day), vitamin E (400 IU per day), and zinc (30 mg per day) are
necessary for thyroid hormone production.
·L-tyrosine (500 mg two or three times a day) also supports normal
thyroid function. May make high blood pressure worse.
·Calcium (1,000 mg per day) and magnesium (200 to 600 mg per day) help
many metabolic processes function normally.
However, once Vitamin C reaches a certain level, our kidneys excrete
amounts over that threshold. This means don't overdo the "C"!
?Ascorbic acid in excess of bodily requirements is excreted, largely
unchanged, in the urine. There is a renal threshold of about 14
mcg/mL, and increasing amounts of ingested ascorbic acid are excreted
unchanged in the urine when the daily intake exceeds 200 mg.
What's wrong with taking high doses of vitamin C?
?Some people believe that because vitamin C is water-soluble, it is
safe to take in high doses. While it is best to not exceed the
recommended upper intake level of 2,000 mg a day, the most serious
possible consequence of an intake above this dosage is diarrhea.
One myth about vitamin C is that it is an antioxidant, but that is not
completely true. Vitamin C is a redox agent, meaning that it acts as
an antioxidant in some cases, and an oxidant in others. Antioxidants
are important because they inhibit chemical reactions with oxygen or
highly reactive free radicals. These reactions (oxidation reactions),
cause damage to cells. Vitamin C only acts as an antioxidant in some
Vitamin C is an important part of a healthy diet. It is not a miracle
drug, and may cause harm if taken in extreme excess. A well-balanced,
varied diet will ensure that you receive more than enough vitamin C to
prevent scurvy and other potential health problems.?
Diseases such as goiter and Graves? cause a thyrotoxicosis
(hyperthyroidism), which requires a larger than normal amount of
Vitamin C to maintain production of T3 and T4. ?Most patients with
Graves? disease have T3 thyrotoxicosis while they are hyperthyroid.
That is, levels of T3 in their blood are proportionately higher to T4
than the ratio seen in normal people. This excess T3 contributes to
many of our symptoms. Our cells also begin to depend on it more for
proper function. Suddenly deprived of T3 when we become hypothyroid
and begin T4 treatment, symptoms of T3 deficiency emerge. For many of
us, those symptoms never abate until we?re treated with either a
combination of synthetic T4 and T3 or glandular extract?
?Thyrotoxicosis increases vitamin C requirements?
?Many nutrients are important for maintaining the health of the
thyroid gland. Vitamin C, vitamin E and the B complex vitamins may
help in the treatment of hyperthyroidism and hypothyroidism because
they play key roles in improving the overall healthy function of the
thyroid gland and the immune system. If you have a sluggish thyroid
you may need to take prescribed supplements under a doctor's
Readers Digest, British Edition
?Vitamin C plays a key role in boosting immune system?and thyroid
gland?function. It's important in the treatment of both
hyperthyroidism and hypothyroidism.?
You can see an illustration here on the connection between the
thyroid, hypothalamus and pituitary glands.
The Thyroid Gland
An interesting story on Hamburger Thyrotoxicosis
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Role ascorbic acid thyroid function
Role ascorbic acid T3 T4
T3 T4 synthesis
Vitamin C production thyroid hormones