Medical News Today: What to know about elevated blood pressure after eating

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When a person measures their blood pressure, the monitor will display two numbers. The upper number represents systolic blood pressure — pressure when the heart is contracting. The bottom number represents diastolic blood pressure, which occurs when the heart muscles relax.

Normal blood pressure readings are under 120/80 millimeters of mercury (mm Hg).

Readings between 120/80 mm Hg and 139/89 mm Hg indicate that a person has prehypertension. This means that they are in danger of developing high blood pressure.

Readings of more than 140/90 mm Hg indicate that a person has hypertension.

Many factors can cause blood pressure to rise and fall. As long as a person’s blood pressure remains under 120/80 mm Hg, there is no cause for concern, unless they experience symptoms of low blood pressure.

High blood pressure after eating is not healthy. A person’s blood pressure usually drops slightly after they have eaten.

Learn more about blood pressure readings and see a blood pressure chart here.

When a person eats, their body redirects blood to the digestive tract to aid with digestion. This causes a temporary decrease in blood pressure elsewhere in the body.

To compensate, blood vessels outside of the digestive tract constrict, causing the heart to beat faster and more forcefully. This helps maintain healthy blood pressure throughout the body.

Some people experience a persistent drop in blood pressure after eating. This happens when the blood vessels outside of the digestive system do not constrict. Doctors refer to this condition as postprandial hypotension, or low blood pressure after eating.

A person with high blood pressure is more likely to experience postprandial hypotension.

Postprandial hypotension can cause complications such as:

Fasting for long periods can also cause a drop in blood pressure. Additionally, it may increase a person’s risk of developing electrolyte imbalances and nutrient deficiencies.

Meanwhile, certain foods can increase a person’s blood pressure after eating: Foods that contain a lot of salt may cause a temporary spike, while foods with saturated fats present a longer-term risk.

People with prehypertension or hypertension should limit their intake of foods that could further increase their blood pressure: foods that contain salt or saturated fat.

Salt

Most processed foods and pre-prepared meals contain high amounts of salt, or sodium. Sodium causes the body to retain excess fluid, and this leads to an increase in blood pressure.

People who experience prehypertension or hypertension should try to limit their sodium intake. Avoid the following foods, which tend to be high in sodium:

• ready meals
• canned soups
• canned vegetables and meats
• potato chips
• marinades and sauces

Saturated fat

Eating a diet high in saturated fat also increases the risk of hypertension. According to the American Heart Association (AHA), saturated fat increases the amount of low-density lipoprotein (LDL), or “bad,” cholesterol in the blood.

High levels of LDL cholesterol lead to a buildup of fatty deposits called plaques in the arteries.

Plaques narrow the arteries, leaving less space for blood to flow. The heart compensates by pumping blood more forcefully, resulting in an increase in blood pressure.

Examples of foods that are high in saturated fats include:

• fatty red meat
• poultry with skin
• lard
• fried foods
• butter
• cheese
• other dairy products
• tropical oils, such as coconut, palm kernel, and palm oils

According to a 2013 review of research into dietary interventions, the following nutrients may help lower a person’s blood pressure:

• Protein: A higher protein intake may increase levels of amino acids in the blood. Some amino acids influence metabolic processes that can help reduce blood pressure.
• Fiber: Fiber helps lower levels of LDL cholesterol in the blood.
• Potassium: Potassium helps the kidneys remove excess sodium from the body.
• Magnesium: Magnesium helps reduce the constriction of blood vessels.

People with hypertension may also benefit from the Dietary Approaches to Stop Hypertension (DASH) diet. This involves eating the following heart-healthy foods:

• vegetables and fruits
• whole grains
• beans
• nuts
• vegetable oils
• fat-free or low-fat dairy products
• fish
• poultry

People following the DASH diet should also restrict or eliminate their intake of foods high in sugar or saturated fat.

The authors of the 2013 review concluded that the DASH diet significantly reduces blood pressure in people with hypertension. Moreover, they found that people who stick to the diet can expect consistent results.

Blood pressure fluctuates throughout the day and night. In order to reliably monitor it, people should take readings at the same time each day.

The AHA provide the following guidelines for measuring blood pressure at home:

• Avoid smoking, drinking alcohol, or exercising in the 30 minutes before a reading.
• Also, ensure that the bladder is empty.
• Sit with the back straight, the legs uncrossed, and both feet flat on the floor. Rest comfortably in this position for 5 minutes before taking a reading.
• Then, rest the arm on a flat surface so that the upper arm is in line with the heart.
• Place the monitor’s cuff on the upper arm, making sure that the bottom of the cuff sits just above the elbow bend.
• Take two or three readings at 1-minute intervals, and record the average value.
• Keep a record of all readings, as this will be useful for longer-term monitoring.

All people aged 20 years or older, regardless of their blood pressure status, should have a blood pressure check at least every year.

People with prehypertension or hypertension require more regular checkups throughout the year.

See a doctor if:

• a blood pressure reading is higher than normal, especially if unusually high readings occur more than once
• blood pressure medication is causing side effects

Ideally, a person can show their doctor a record of their blood pressure readings. This will assist in a diagnosis and ensure that the doctor is prescribing the most appropriate treatments.

A person’s blood pressure typically drops slightly following a meal. However, foods high in sodium can cause a temporary increase in blood pressure, while foods high in saturated fat can cause longer-term issues.

People who have prehypertension or hypertension should limit their intake of foods high in sodium or saturated fat, and replace them with foods high in fiber or protein.

See a doctor if blood pressure exceeds the normal range at any time, including after eating. The doctor may recommend taking medication.