McCarron Article

Question 1

2) According to the author, what were the assumptions on which the low sodium health policy was based?

Answer 1

1. Current intakes are excessive
2. Health ranges must be below current intakes
3. Sodium intake can be substantially reduced by public policy
4. Human intake of sodium is dictated by the sodium content of the food supply
5. Lower sodium intake is always better (unlike all other nutrient distributions which follow a Gaussian distribution).

Question 2

3) What evidence does the author provide to support his argument that “public policy cannot change sodium intake because intake is set by human physiology”?

Answer 2

The authors describe data from two large studies aimed at decreasing sodium intake coupled with intense dietary counseling. In the TOHP II (Trials of Hypertension Prevention II), despite the target goal of sodium intake being 2000 mg per day, subjects were not able to achieve that target and consumed an average of 2530-2645 mg/day.
Another argument is the British experience with a campaign that initiated in 2006 to lower sodium intake in the population. This included nationwide social marketing, commitment from food manufacturers to decrease sodium content of common foods and promotion of lower sodium foods among retailers. Three years later, this effort resulted in a decrease in sodium intake, as assessed by 24-hour urinary sodium excretion value, of 12%, which rather than a true decrease, was just a variation around a mean intake of 3700 mg/d.

Question 3

4) What is the argument used by the author to justify NOT reducing sodium intake in patients with congestive heart failure and renal disease?

Answer 3

First we must characterize the pathophysiology of these diseases: these patients usually have elevated plasma renin and angiotensin II and elevated sodium intake.
The author argues that these populations have a higher sodium intake as a compensatory response mechanism to increase renal perfusion and suppress renin secretion, and therefore, decreasing their sodium intake would lead to further increases in renin and angiotensin, which could contribute to further progression of disease.

Question 4

• To convert mmol of sodium to mg of sodium, multiply mmol by 23.

Answer 4

K

Question 5

1) According to the author, what are the normal ranges of sodium intake in world populations?

Answer 5

2650 to 4830 mg/d (mean=3700 mg/d) in data from 33 countries collected from 1982-2008
3526 mg/d from 38 studies conducted in the US from 1957-2003
2622 to 4830 mg/d (mean = 3666 mg/d) from combined data sets 2009 and 2013.