Kidneys, Insulin and Salt Retention

June 29, 2015

Why You Can Lose/Gain 5 Pounds in One Day – Insulin, Kidneys and Salt 

 June 29th, 2015 

 Reference: Horita, Int Jr of Hypertension 

 Ever stepped on the scales and gained five pounds in a day?   Better yet, ever started a diet and lost 5 pounds the first week? “It’s just water weight, “ you say. And you are correct. But the details are pretty elaborate. Here are the details, as elaborated by Horita in his review article.   There are likely four or five key reasons why being overweight leads to high blood pressure, but leptin resistance is certainly in the mix.   

Leptin is your “stop eating hormone” made by fat cells that goes back to your brain and signals that you have had enough to eat. As we get overweight, we become leptin resistant. Long term elevated leptin leads to increased adrenaline in the blood, raising blood pressure. And as we get heavier, we also become insulin resistant, with gradually rising blood insulin first, then rising glucose later.   

In addition to leptin, there are arcane hormones such as tumor necrosis factor (TNF) that causes sodium excretion at high concentrations and retention at low concentrations.   Figure that out?!@   Or angiotensin that saves salt and is closely related to insulin resistance.   Then, there is the WNK family with its five subtypes and you get the picture of increasing complexity. Insulin affects all the WNKs. Whew. 

 But what is the effect of insulin on the kidney? That is the key to discuss today.   Insulin, the hormone your body makes to store glucose, has another effect entirely on the kidney. It essentially turns on sodium retention in virtually every part of the kidney.   When you save sodium, you save water too.   When you hang onto water, you increase the volume of your vascular tree. (Blood vessels.)   That’s a bit like adding more water to a fixed size water balloon. The pressure has to go up.   Now, interestingly enough, insulin also stimulates the production of nitric oxide, the chemical your body uses to relax your blood vessels, making your total volume of body water go up. So, your balloon gets a bit bigger.  

 Did you get that? With a bigger balloon, you gain water weight. With insulin, you stuff more water in it. This becomes a pretty simply formula to gain weight.   A piece of chocolate cake for dessert is just 200 calories and weighs less than 4 ounces. But you add ice cream on the side and you just turned on insulin in a dramatic fashion.   With that you start the whole cascade of saving salt water.   You gain 5 pounds. 

 And what happens when you diet?   You avoid carbs and sugar for a day or two. You just eat “salad”. Salad is composed of low glycemic spinach and arugula, with tomatoes and cucumbers, topped with olive oil – none of which stimulates insulin. Your insulin level starts to fall.   If you are overweight, your insulin level starts out at 11-20, which is supposedly normal, but enough to stimulate sodium retention.   After a few days of consistently low glycemic food, and fat, your insulin level keeps drifting down and your kidneys get the memo, “No insulin”.   Your retention of sodium slows down dramatically, your volume of distribution, the size of your water balloon, shrinks. Your weight suddenly looks like you just lost 5 pounds.   Voila, you feel so proud. This is the mechanism of every ad shouting at you, “Lose 15 pounds in the first two weeks”.   You can lose 15 pounds in the first two weeks.   Thirteen and a half of water.   

You actually lost one and a half fat pounds! But that’s one and a half you weren’t able to lose before. Just don’t get discouraged when those 13 come back. 

 WWW.   What will work for me?   If you weigh yourself daily, you see your weight bounce up and down by 3-5 pounds all the time.   When I stay off carbs completely for 4 days in a row, I feel mercilessly dizzy if I don’t eat extra salt.   With that extra salt, usually, in the form of Tobasco sauce or “Slap Ya Mama” Cajun spice, I feel just fine.   And my blood pressure is down 15-20 points in just a week. If my blood pressure can do it, so can yours!   What’s the wise person to do? Calculate your basal metabolic rate for your age, height, weight and gender, add your exercise calories, and eat less calories a day than that result.   Make sure they are low glycemic vegetables, fat and modest protein calories.   And watch your blood pressure fall.   

Pop Quiz

  1. Insulin, your natural calorie storage hormone also affects how much salt your kidneys hang on to. How?                        Answer:  By stimulating your kidneys to reabsorb most of the salt that passes through
  1. Insulin also increases the size of your body water? T or F                        Answer:  True. It stimulates Nitric Oxide production which increases the “size of the water balloon.”
  1. Insulin resistance is strongly related to high blood pressure. T or F                  Answer:  True. (If you didn’t get this one by now, I would be distressed)
  1. It makes sense to lump high blood pressure together with high blood glucose, cholesterol and high insulin.   T or F                     Answer:   True. That’s why we call the collection of them the metabolic syndrome.
  1. Fat has no effect on insulin. T or F                     Answer:   True.   As long as it’s natural fat, not manufactured, transfat or vegetable oil.
  1. You can lower your blood pressure by getting off sugar, wheat, flour, bread and all root vegetables and grains. T or F                      Answer:   Bingo.   Give it a try.