Not everyone gets high blood pressure from taking in too
much salt. The people who are most likely to get high blood
pressure from taking in too much salt are those whose cells do
not respond well to insulin (Hypertension, Jan 2013). People
whose cells do not respond well to insulin are called "insulin
resistant". On the other hand, those whose cells respond well
to insulin are called "insulin sensitive". They can develop high
blood pressure from not taking in enough salt.
SALT RESTRICTION ISN'T FOR EVERYONE. Thirty-five years
ago, researchers first described people whose blood pressure and
weight rise when they take in extra salt. They are called "salt
sensitive". They gain weight because their kidneys cannot get rid
of the extra salt. The extra weight is caused by retaining extra
fluid. Eventually, taking too much salt can cause salt-sensitive
people to suffer kidney damage as evidenced by leaking protein
(albumin) into their urine. (Diabetes Res Clin Pract, April 1998;39
Suppl:S15-26). Those who do not develop high blood pressure when
they take in large amounts of salt are called "salt insensitive".
DEFINITION OF INSULIN RESISTANCE: Most cases of high blood
sugar in diabetics are caused by inability of cells to respond to
insulin, not by lack of insulin. Before insulin can do its job
of driving sugar from the bloodstream into cells, it must first
attach to special hooks on the outer cell surface called insulin
receptors. Anything that blocks insulin from attaching to its
receptors on the surface of cells can cause high blood sugar
levels and high blood pressure. People who respond normally to
insulin usually do not get high blood pressure from taking in too
much salt. Insulin receptors are blocked by eating red meat,
eating animal saturated fat, lack of exercise, excess fat in fat
cells, overweight, fat stored in the belly, not eating enough
fruits and vegetables, and lack of vitamin D.
THIS STUDY: People who are salt sensitive and have high
blood pressure are usually fatter, and have higher blood levels
of creatinine, cholesterol, aldosterone, glucose and insulin
(Hypertension, Jan 2013).
• Creatinine goes up when the kindeys are damaged.
• Aldosterone is secreted by the adrenal glands to cause the body
to retain salt.
• Blood sugar goes up when insulin receptors are blocked.
• Insulin goes up when blood sugar levels rise.
SALT-SENSITIVE PEOPLE HAVE A HIGH RISE IN INSULIN WHEN THEY
TAKE IN EXTRA SALT. Fasting blood sugar levels are usually
normal and did not differ between salt sensitive and salt
resistant people with high blood pressure
regardless of how much salt they took in. However fasting blood
levels of insulin increased in salt sensitive patients when they
took in extra salt (Am J Hypertens, 1998 (Apr);11(4 Pt 1):397-402). .
The extra salt causes high insulin levels which constrict
arteries to raise blood pressure. People who have insulin
resistance at low salt intake will have much more insulin
resistance at a higher intake of salt. For them, a high salt
intake increases blood pressure, insulin, and blood sugar.
HOW TO TELL IF YOU ARE INSULIN INSENSITIVE AND THEREFORE
PROBABLY SHOULD RESTRICT SALT: People who are insulin insensitive
usually have what is called metabolic syndrome. You have
metabolic syndrome if you have any three of the following
• storing fat primarily in your belly
• having small hips
• being overweight
• having blood triglycerides (>150)
• having blood HDL cholesterol (<40 br="">
• having a fatty liver
• having a fasting blood sugar >100 (HbA1c> 5.7)
• having high insulin levels
• having high blood pressure
EVERYONE SHOULD CHECK HIS OR HER BLOOD PRESSURE: Get a
blood pressure cuff. Take your blood pressure just before you go
to bed. If your systolic blood pressure is above 120 much of the
time, you have high blood pressure and should check with your
doctor to see if you are salt sensitive and therefore, should
restrict salt (and make other lifestyle changes).