A couple of weeks ago I (hopefully) dispelled the notion that black pepper is unhealthy.

Since I posted that item several people have quoted research showing that although black pepper may not be unhealthy,  red peppers certainly are. They have a point. But it is not that simple. Red peppers may be good or bad for us but, as is the case with all potentially beneficial substances, it all depends on the therapeutic index.

The therapeutic index is the ratio of the quantity of a substance (usually a medicine) that causes toxic effects, to the amount of that substance that is required to produce a therapeutic response. The higher the therapeutic index the safer the substance.

Almost anything can be toxic if you take too much of it. Most fruit and vegetables that are vital to good health (broccoli comes to mind) contain toxic compounds. Some of these compounds are considered carcinogenic in large doses and yet when consumed in small quantities they often help to prevent cancer! It is extremely difficult to eat toxic quantities of fruit and vegetables as the 'bad' compounds that they contain have very high therapeutic indices.

Some other foods (barbequed meat, for example) contain harmful compounds that have much lower therapeutic indices than those found in fruit, vegetables and spices.

Chilies and some other red pepper species contain capsaicin, a compound that is being researched as a potential treatment for cancer.  The "hotness" of a chili depends on the concentration of capsaicin in the fruit. For instance habanero chilies contain far more capsaicin than the much milder anaheim variety.

Although capsaicin's therapeutic index has not been measured, available evidence indicates that it may be lower than those of many other plant compounds. Recent research has shown that, although it may help to protect against lung and prostate cancer, in very high quantities it could possibly trigger cancer of the stomach. Even though this evidence is far from conclusive it would be prudent not to overdo the consumption of really hot chilies as capsaicin could possibly be a "sharp" double-edged sword.

Hot is definitely healthy but remember that 'the danger is in the dose' and it is far better to eat a range of spices, fruit and vegetables than vast amounts of one or two favorites.

Other strong, healthy spices that do not rely on capsaicin for their health or hotness are black pepper (piperine) and the brassicas; mustard, wasabi and horseradish (isothiocyanates).

A good way to get a balanced intake of the best spices is to take a spice supplement .