Coffee is usually regarded as something tasty that — when one has to stay awake for studying for exams or other urgent activity — keeps you awake. But the drink has recently been found to produce a variety of other health benefits, according to a survey article published in the latest issue of the Hebrew-language Israeli Journal of Family Practice.

Professor Yair Yodfat, a family medicine expert at the Hebrew University-Hadassah Medical School and an adviser on hypertension to Sheba Medical Center at Tel Hashomer, writes that he is often asked by patients whether coffee drinking can raise blood pressure.

He replies that, based on recent studies, coffee and its caffeine — if consumed in moderate amounts — not only don’t have a bad influence on existing disorders, but can also help prevent diseases or prevent those that exist from getting worse.

The body can adapt itself to caffeine, he said, and for some people can even allow them to fall asleep not long after having a cup.

A stimulant, caffeine influences the release of a variety of neurotransmitters such as noradrenalin, acetylcholine, and dopamine. It causes certain blood vessels to expand and others to constrict, while it also increases muscular ability.

It may ease some headaches by increasing the blood flow to the brain.

Yet some people are particularly sensitive to caffeine, which can cause them difficulty sleeping, anxiety, nervousness, depression, stomach problems, or a rapid heartbeat.

Anyone who has experienced such a reaction from drinking coffee should stay away, he writes.

Consuming more than 600 milligrams of caffeine a day — a cup of instant coffee has 40 to 104 mg, while an espresso has 100 in a small cup and percolated coffee 80 to 135 — can cause upsetting symptoms and should be avoided. Chocolate, tea, and cola also contain caffeine.

Studies have shown that moderate coffee drinking that begins gradually, instead of suddenly, can raise blood pressure a bit but does not speed up heartbeat, writes Yodfat.

The Iowa Women’s Health Study that observed 23,000 menopausal women over 11 years found that those who drank more than six cups of coffee (including caffeine-free) a day had a 22 percent lower risk of contracting Type 2 diabetes than those who did not drink coffee.

A meta-analysis of 18 studies with 500,000 participants showed that every cup of coffee drunk a day reduced by 7 percent the risk of getting Type 2 diabetes.

It is believed the connection is an increase in the hormone adiponectin, which is connected with insulin resistance.

Other studies showed there was no connection between coffee drinking and heart attacks, strokes, or sudden death. In addition, moderate coffee drinking has not been found to cause harm to pregnant women or their fetuses.

Coffee or tea drinkers do not have a higher risk of breast, liver, or colon cancer.

As most of the studies cited were retrospective (looking back) rather than prospective (following up people for years and observing changes due to their behaviors), Yodfat notes that more such studies should be carried out. He urges people to consult with their doctor before making dietary changes and to avoid excessive coffee drinking.