Interesting subjects. Let's see what i can write about it.
Vitamin D deficiency leans to increased levels of parathyroid hormone and can mess with Calcium and Phosphorus homeostasis. Symptoms in children are restlessness, irritability, excessive sweating and impaired appetite. Prolonged vitamin D deficiency leads to rickets (developmental delay and skeletal abnormalities in children). This happen because the bones are failing to accrue sufficient Calcium and Phosphorus and because of this arms and legs become bowed, tooth enamel has inadequate mineralization, and in very severe cases the low level of Calcium affects the nerves and may cause seizures.
Symptoms in adults are softening bones (osteomalacia) and slowly becoming deficient in Calcium and Phosphorus. First signs are bone and muscle pains, progressing to muscle weakness and spasms. When severe, you can have brittle bones, associations with osteoporosis, increased risk of falls (more fractures and muscle weakness than average).
When acute, you have loss of appetite, weight loss, increased urine production, heart arrhythmia, and some serious effects like high blood calcium level leading to urinary tract stones, vascular and tissue calcification (damaging the heart, blood vessels, kidneys). Excessive sun exposure is not increasing the vitamin D to toxic levels, as heat will also degrade the newly formed vitamin D.
Long term intake of vitamin D increases the risk of dying, cancer, cardiovascular events, increasing the number of falls in elderly. High circulating calcium levels leads to increased bone calcium loss, excessive urinary Calcium excretion, thirs, vomiting, loss of appetite, lethargy, dehydration, constipation and muscle spasm.
Next post will relate to vitamin E.
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Disclaimer: This text also can be re-published on my personal blogs, such as this one.