Dear Dr. Mo: You’ve mentioned that Squash is rich in vitamin A but cautioned not to take too much of it. How can vitamins hurt us? Specifically, why is vitamin A important and how can it be harmful? What’s happening in vitamins deficiency?
Dear reader: Vitamin A has many vital functions and people associate it with good vision and this is certainly true. This vitamin along with vitamins D,E and K is not water soluble, which means they are not easily removed from our body and can hang on for a long time in our fat tissue, being fat-soluble. That’s why too much of it will stick around and cause problems. Apart from good vision, here are a few other equally significant roles of vitamin A in normal, deficient and excess situation:
1. It is a cofactor for a hormone called PTH (Parathyroid hormone) and this means that without it the hormone cannot function properly. PTH is necessary for Calcium balance in our body – this means that PTH controls the levels of Calcium in our blood; it affects the strength and health of our bones, the absorption of Calcium from our gut etc. Except for bone health, Calcium is also very important in cellular functioning and without it (or with too much of it) many of our vital processes stop or become excessive (for example, muscle contractions including heart, secretion of hormones like for instance insulin etc..).
Contrary to deficiency, vitamin A excess will cause PTH to work too much and increase levels of Calcium at the expense of our bones; too much Calcium will cause problems with muscle contractions known as tetanic contractions, our heart will not beat properly, kidneys may develop stones, Calcium will leak out into urine and the entire system will be thrown off balance.
2. It’s necessary for production of the fluid that cushions and maintains our brain and spinal cord called Cerebro-Spinal Fluid (CSF) – in vitamin A deficiency the CSF production is low but the body doesn’t know it; on the flip side of it, if vitamin A is in excess, too much CSF will cause dangerous increase in pressure in the skull which manifests itself with strong headaches and optic nerve swelling and can lead if left untreated to blindness and/or even death via something called brain herniation.
3. It’s crucial in maturation of cells such as the ones in hair, skin and eyes or linings of our organs like the lungs or intestines. So if for example a child is recovering from Measles, a doctor may give some vitamin A to speed up the regeneration of the child’s worn away cells in the lungs. We also give vitamin A to transform one exceptionally lethal type of Leukemia called PML (Pro-Myeloblastic Leukemia) into one less lethal called AML to help patients live longer with the disease. Vitamin A is used in Dermatology to manage some diseases etc.
4. As I mentioned, it is a key to good vision, especially the one in poor light – night vision. So if you notice that your vision is impaired at dusk or in the dark, and similar low lighting conditions you may have vitamin A deficiency.
5. It’s a mild antioxidant and the theory goes that antioxidants help us fight against oxidative stresses and prevent cancers from forming, help fight off infections more efficiently, slow down aging etc. but the public scientific debate is current about whether or not this theory really holds any water; we’ll just have to wait and see but this may only show that antioxidants in pills and other supplements are nothing but hot air while the ones in food will remain beneficial in interaction with other nutrients the food provides.
So as with any situation of deficiency, it creates a version of a Low Energy State and the first sign is the same: shortness of breath (manifested as rapid and/or difficult breathing); the first symptom will be the same: weakness (which may progress into fatigue). Many may only experience tired legs or just a generalized lack of energy for no particular reason.
The skin will be dry, nails will be dry and brittle, hair will be dry, breasts will atrophy, reproductive potential will decrease (may result in infertility), first infections to occur will be respiratory/pulmonary and urinary infections, bone marrow will be suppressed, which means the immunity and blood’s ability to carry oxygen will go down and allow for more infections and eventually even cancers – first cancers will usually be skin, gastrointestinal and bone marrow cancers. Kidneys may start failing too.
In case of very severe and untreated vitamin deficiency, the most common direct cause of death is heart failure.
This is not typical for vitamin A deficiency but for any vitamin or other nutrient deficiency, which is needed for daily normal functions of our body.
Remember that each of these deficiencies produce a Low Energy State and the resulting consequences are identical.
Yours in health,