Letters.

Magnesium missing link

Regarding "Depression linked to heart deaths" (SN: 3/31/01, p. 205): Depression is a common symptom of magnesium deficiency. Heart attacks, including fatal heart attacks, are also a common symptom of magnesium deficiency. It is thus no surprise that depressed people have a higher-than-normal rate of fatal heart attacks.

Bernard Rimland Autism Research Institute San Diego, Calif.

Heads up

"Early Brazilians unveil African look" (SN: 4/7/01, p. 212) was a very interesting article containing an interesting idea. But some of us guessed the connection all along. Check out Olmec-age stones heads [in the Americas]. These images are African. However, it's a good bet that migration came from both Asia and Africa.

Gloria Harrison Raleigh, N.C

Merciful higher powers

Regarding "Cold sliver may sense electron quiver" (4/7/01, p. 221), micro-, nano-, and pico- are fine. But have mercy and explain zepto-!

Joel Faitsch Pittsfield, Mass.

The prefix zepto- refers to an amount represented by [10.sup.-21], or a billionth of a trillionth.

--P. Weiss

Right on, boron 

In reference to "Boosting boron could be healthful" (SN: 4/14/01, p. 228), it's important to note that there's no risk in aiming for a high-boron diet. Eighty percent of Americans fall short when it comes to dietary recommendations for fruit, nut, and legume intake. Eating four servings of fruit and a handful of nuts per day, could bring boron intake up to 3 to 6 milligrams per day. Some healthful diets contain 9 to 13 mg of boron per day, which is still below the safe upper level of 20 mg/day.

Charlene Rainey Food Research Inc. Costa Mesa, Calif.

Your article on boron as a micronutrient was very interesting, but I was confused by the last paragraph. It says we eat too few nuts but also recommends peanuts, which are legumes, not nuts.

HR. Maltrud Los Alamos, N.M.

Both tree nuts and peanuts tend to be rich sources of boron.

--J. Raloff