American children eat too much salt, and those who eat the most have higher blood pressure, a new study finds. The study came from the U.S. Centers for Disease Control and Prevention. Researchers looked at data on 6,200 children who took part in recent national health surveys. The children were ages 8 through 18. Children were asked twice over several days to list all foods they had eaten the day before. Researchers estimated how much sodium they ate. Salt is the biggest source of sodium in food. On average, children ate 3,300 milligrams daily. That's 1,000 milligrams above the recommended amount. Overall, 15% of children had either prehypertension or high blood pressure. Prehypertension is blood pressure that is above normal but not as high as in high blood pressure. Children who ate the most salt were twice as likely to have one of these conditions as children who ate the least. Rates were triple for overweight and obese children eating the most salt. The journal Pediatrics published the study online September 17. The Associated Press wrote about it. Another study in the journal found that children's doctors don't always check blood pressure. They measured it at one-third of all visits and two-thirds of checkups.

By Henry H. Bernstein, D.O.
Harvard Medical School

What Is the Doctor's Reaction?

Many people think only adults can have high blood pressure (hypertension). Think again! Studies show that about 1 in 20 children have higher than normal blood pressure.

Children with high blood pressure are more likely to have high blood pressure as adults. This puts them at increased risk for serious diseases later on in life, such as heart or kidney disease.

A new study published in the journal Pediatrics looked at how often children's doctors routinely took blood pressure measurements during office visits.

Between 2000 and 2009, doctors started checking blood pressure in children more often. There is still room for improvement, though. Researchers found blood pressure was only tested at:

• About one-third of all visits (sick and checkups) to the pediatrician
• About two-thirds of checkup visits
• About 84% of checkups when a child was diagnosed as overweight or obese

It seems that pediatricians are doing a good job of checking the blood pressure of children who are older and overweight or obese. But other children with normal weights must also be checked. The rate of blood pressure testing was especially low for younger children (3 to 7 years old).

A second study published this week in the same journal also looked at blood pressure in children. It included U.S. children and teens ages 8 through 18. Researchers focused on the connection between high blood pressure and the amount of salt in a child's diet.

• The average salt (sodium) intake was more than 3,300
milligrams per day. No more than 2,300 is the recommended amount.
• Salt intake increased as children got older.
• Children who ate more salt:
  
  • Had higher systolic blood pressure (when the heart is squeezing to pump blood) than those with low-salt diets.
  • Were at higher risk for prehypertension or high blood pressure.

This second study suggests that the effect of salt intake on blood pressure may be an even bigger problem for children who are overweight or obese than for children with a normal weight.

We know that the best way to find high blood pressure in children is with regular blood pressure testing. It appears that pediatricians need to measure the blood pressure in children more often. They also need to pay closer attention to how much salt children eat.

What Changes Can I Make Now?

The only way to know whether your child has high blood pressure is to get it checked. So it is important not to miss regular checkups.

Doctors should begin to measure blood pressure during routine checkups when children are 3 years old. This is especially important if your child is obese or if there is a family history of high blood pressure. These children are at higher risk for having high blood pressure themselves.

If an illness is causing your child's high blood pressure, treating this illness may be enough to get the blood pressure back to normal. If there is no underlying illness, high blood pressure can be controlled through:

• Changes in diet
• More physical activity
• Maybe taking a medicine
• A combination of these three measures

If obesity is the cause of your child's high blood pressure, the first step is to help your child lose weight. Physical activity seems to help control blood pressure. Losing weight and doing more exercise can change mild high blood pressure to normal. Exercise also provides many other health benefits.

The next step is to limit the salt in your child's diet. Not using any table salt and restricting salty foods can reverse mild high blood pressure. These steps also will help lower more serious blood pressure levels.

Be careful when shopping for packaged foods, too. Most canned and processed foods are full of salt. Check labels carefully. Make sure what your family is eating has little or no salt added.

Most doctors prefer not to give medicine to children with mild high blood pressure. However, if diet and exercise changes do not bring improvement, medicine may be needed.

Continue to follow your doctor's advice once your child's blood pressure is back to normal. Stopping treatment can result in the high blood pressure coming back!

What Can I Expect Looking to the Future?

Researchers will continue to study how high blood pressure in children affects them when they become adults.

You can expect blood pressure to be tested more regularly on all children. Keeping a healthy weight will lower your child's risk for high blood pressure. So you also should hear more about the importance of good eating habits and lots of physical activity.