Most shark attacks occur less than 100 feet from the shore. More people are killed by bee stings and lightning than by shark attacks. Worldwide about 30 people die each year from shark attacks, which means a person has a one in 300 million chance of being killed by a shark. A shark attack most often occurs when a shark mistakes a person for a seal or other animal.
The new 2010 recommended daily allowance (RDA) is 600 IU for those 1-70 years of age and pregnant or breastfeeding women, and 800 IU for those over 71 years of age. An adequate blood level of vitamin D is 20 nanograms per milliliter, which can be achieved through daily skin exposure to sunlight.
1 For people over 50 (and postmenopausal women): 400-800 i.u. of vitamin D per day. 2  For people over 65 or 70, at least 600 i.u. is usually recommended. 3  For people 25-50 years old (and premenopausal women): 400 i.u. of vitamin D per day.he recommended amounts of calcium for adults are as follows: 1  For pre-menopausal women 25-50 years old and post-menopausal women on estrogen replacement therapy: 1,000-1,200 milligrams of calcium per day.