How Diabetics, Too, Can Fast on Yom Kippur

A primer to help the different kinds of diabetes patients ring in a healthy Jewish New Year.

Daniel Bar-On

In 19th-century Europe, diabetes was considered “the Jews’ disease” because many Jews worked in professions where they got little exercise, suffered from obesity and contracted diabetes. But the disease gradually became a global plague.

Yom Kippur is a challenging meeting place between the 25-hour fast and diabetics who choose to fast. Many patients take medication every day to lower their blood sugar. If they don’t eat, these levels could decrease, rendering the medication unnecessary and even dangerous by lowering blood sugar too much.

So here are a few pointers on how diabetics can fast safely.

Those who can fast with no problem. These are patients with Type 2 diabetes (formerly known as adult-onset diabetes) who do not take medication and simply follow a healthy lifestyle, or who take one pill per day — the kind that does not lower blood sugar beyond a certain threshold.

Even without food, these patients’ blood-sugar levels cannot become dangerously low. So on Yom Kippur, these diabetics should take their one pill per day at the pre-fast meal, and another pill when the fast ends.

Those who can fast under certain conditions. This applies to patients with Type 2 diabetes who take insulin to lower blood sugar or pills that do not have that lower threshold. Thus there's the threat that blood-sugar levels can fall low enough to endanger a patient’s life. These patients can fast, but must take into account that abstaining from food prevents blood sugar from rising.

In this situation, medications that lower blood sugar could overcompensate; blood sugar could drop sharply and dangerously — what is known as hypoglycemia. Thus patients who do not know how the fast will affect their blood sugar and can’t forgo their medication should not fast.

Patients who take these medications and still wish to fast should use a home monitoring device to keep track of blood sugar throughout the day — in the morning, at noon, in the afternoon, in the evening and before sleep. They must also let family members or friends know that they are fasting so they can receive help if they feel dizzy, weak or faint — early signs of hypoglycemia.

Fasting with insulin. Patients with Type 1 diabetes (formerly known as juvenile diabetes) who take insulin must continue taking it even during the fast. This is because the body needs two kinds of insulin: basal insulin, a low-level insulin that covers the body’s need for the hormone between meals and at night, and rapid-acting insulin, which is taken before meals.

Patients with Type 2 diabetes have a reserve of basal insulin, while patients with Type 1 diabetes have no insulin at all. They must monitor their blood sugar frequently throughout the fast and prevent any decrease.

People who should not fast. Women who have gestational diabetes or had diabetes before becoming pregnant should not fast. There is a link between unbalanced blood-sugar levels and harm to the fetus, problems during childbirth and a general risk to the mother’s health. For example, if the mother’s blood sugar is high, the fetus will use the surplus sugar to help grow — not something desirable at this stage.

Diabetics with other diseases linked to diabetes should not fast either. Remember that sugar is the body’s main source of energy. Low blood sugar caused by not eating can cause weakness; this applies all the more to diabetics who suffer from additional illnesses.

Others who should not fast include diabetics who suffer from sudden hypoglycemia (usually from overdoses of medication or from eating less), diabetics who have felt ill while fasting in the past, and patients who have suffered diabetic acidosis — a sharp increase in blood sugar.

(When the body does not take in food for a long time, it signals for the release of glycogen, a hormone that causes the liver to convert the sugar stored in its glucose reserves. This mechanism, along with abstention from the medications that lower blood sugar, can cause blood sugar to spike dangerously in some patients.)

As Yom Kippur approaches, some doctors suggest that diabetics change their treatment for the fast. For example, some recommend replacing a certain medication before the fast to prevent a decrease or increase in blood sugar.

I don’t recommend that my patients change the medications that they and their bodies have been accustomed to for years. Remember that while blood sugar can be kept balanced during a fast in most cases, each patient has his specific needs.

I wish you an easy fast.

Dr. Julio Wainstein heads the diabetes clinic at Wolfson Medical Center and is a member of the advisory board at the Diabetes Medical Center in Tel Aviv.