Question

How many mmols of calcium and potassium does someone over the age of 60 need to eat, maximum and minimum amount?

Answer

First let us emphasise that most people on a normal western diet almost certainly have adequate calcium and potassium intake, unless there are certain types of food that they do not eat for some reason or other. Although calcium and potassium are both important, it does not mean that more of a good thing is better than an adequate amount, hence the maximum amount is as important as the minimum amount.

The amount of calcium in the body and in the blood depends on what is taken in by mouth, what is excreted through the kidneys and what is reabsorbed and deposited in the bones. The bones, of course, are the largest source of calcium in the body. In normal people, the total amount of calcium absorbed from the gut matches the urinary excretion, and taking more calcium in the diet just increases the amount in the faeces or increases the amount excreted by the kidneys. The amount of calcium that is absorbed from the gut depends on a number of factors, but particularly on vitamin D. Overall, humans are able to adapt to variations in dietary intake of calcium, so that the net absorption remains relatively constant over a fairly wide range of intake. Calcium is particularly available from milk and dairy products but is also present in breads and cereals.

Most of the potassium in the body is inside cells. The amount in the body is controlled by a number of hormones, and excretion takes place through the kidneys. If the oral intake is increased, the kidneys are able to excrete 10-20 times more than in normal circumstances. Potassium is found in vegetables and fruits, lean meats, poultry, fish, eggs, nuts, seeds and pulses.

The recommended intake for males and females over the age of 50 is 17.5 mmols per day of calcium. Adequate potassium will be taken if 5 fruits or helpings of vegetables (that is a total of 5 vegetables and/or fruits) are taken per day.

Our overall advice for both calcium and potassium is that supplements are not required in normal people and that an adequate intake of food from each of the 4 major food groups (vegetables and fruits, breads and cereals, milk and dairy products, and lean meats, poultry, fish, eggs, nuts or pulses) is all that is required.