DEAR DR. BLONZ: I support the idea of whole foods, but I am constantly reading that the soil is depleted of minerals, which makes the produce we eat insufficient to give our bodies the nutrients we need. It is my understanding that produce requires its nutrients to grow to proper size, shape, color, form, taste, etc. Therefore, it seems logical to me that the produce does not have sufficient nutrients as it has had in the previous hundred years (or more). Please advise. - R.B., Arlington Heights, Ill.

DEAR R.B.: You are partially correct. Plants act as miners, pulling out of the soil the mineral elements that they need to grow. If a mineral needed by the plant is unavailable, the plant will not grow. It is incorrect, though, to think that today's fruit, vegetable or grain will provide less of these nutrients than the same variety would have provided in the past. Plants synthesize their own vitamins, so they will be there as the plant grows.

There is another layer to this question, however, as nonessential minerals present in the soil can also end up in a plant. Whole foods grown in iodine-rich or selenium-rich soils, for example, can have more of these nutrients than the same type of food grown in soils with lesser amounts.

What gets pulled in differs from plant to plant and mineral to mineral - even among different varieties of the same fruit, vegetable or grain. The plant's overall nutrient content can also vary according to the time of the growing season and the length of time the plant has had to grow. This means that a plant picked green may not have the same nutrient content as one allowed to ripen.

It is difficult to speak with any statistical surety because we don't have records of nutrient content from the produce of 100 years ago. Based on what we know, however, it's likely that the amounts would be comparable.

DEAR DR. BLONZ: I had my baby a month ago and have been experiencing the "baby blues." I am no longer having severe after-birth cramping, just occasional moderate to mild cramps. My milk supply is now at full capacity, but I remember having more milk with my first son. The last few days, my nipples have been sore and red. My husband brought home a bottle of fresh black cohosh root. I've read that this herb helps with female hormonal balance and relieves cramping. I am breast feeding, so I am wondering if it would be safe for my baby if I were to take black cohosh. If so, how much is a safe dose? Also, do I even have a need for this herb? If not, is there an alternative you might suggest? - C.W., via e-mail

DEAR C.W.: I offer you congratulations on the birth of your child, but I also offer warnings about the use of black cohosh. It is not recommended for women who are pregnant or breastfeeding. Warnings to this effect were just put out by the United Kingdom Department of Health. A copy of the warning can be found online at tinyurl.com/fxeny.

In general, you can't assume that this or any herb is safe to use during this important period. An herb may, in fact, be totally innocuous, but it could cause problems ranging from colic to interference with proper growth and development. The sad fact is that we simply don't know. Always err on the side of caution. Please consult with your health professional to see whether there might be a preparation that could assist with your concerns. You should also consider contacting the La Leche League for anything related to breastfeeding (www.lalecheleague.org).

Send questions to: "On Nutrition," Ed Blonz, c/o Newspaper Enterprise Association, 200 Madison Ave., New York, NY 10016. For e-mail, address inquiries to: ed@blonz.com. Due to the volume of mail, personal replies cannot be provided.

Ed Blonz, Ph.D., is a nutrition scientist and the author of "Power Nutrition" (Signet, 1998) and the "Your Personal Nutritionist" book series (Signet, 1996).