According to a recent symposium on Vitamin D and breast cancer in London, (Carole Baggerly, Cedric Garland) it is advisable to maintain the level of vitamin D in the serum to 100 - 150 nmol/ml (40 to 60 ng/ml).
I got the Vit D levels of all my family members, and all of them were on the lower side of normal. I would suggest to the readers of this blog to consider getting their Vit D3 levels as also Vit B12 levels (for those who are pure vegetarians).
And to put forth the old saying, 'An apple a day keeps the doctor away". There is so much truth in that. It's not about the apple, but fruits in general. We must ensure a daily intake of fruits, especially citrus fruits.