April 2013 - Researchers from the London School of Hygiene & Tropical Medicine reported
that the number of people in England who add salt to their food at the table fell by more than
a quarter in the 5 years after a national campaign in 2003.
Previous research has shown that the national salt reduction campaign by the UK Food Standards Agency and the Department of Health
raised public awareness and led to cooperation wfrom the food industry to reduce salt levels in processed and there was a small overall
reduction in salt intake. The research published in the British Journal of Nutrition is the first to look at the amount of salt people
add at the table.
The London School of Hygiene & Tropical Medicine researchers looked at salt intake from 1997-2007 by
more than 6,000 adults living in England. Since the campaign launched in 2003, the proportion of people saying
they added salt at the table fell from 32.5% to 23.2% in the following 5 years.
According to Jennifer Sutherland:
"Salt use at the table accounts for 15-20%
of total salt intake. Our study shows that from 1997-2007 there was a steady decline in salt use at the table, but this reduction was greater
after the introduction of the salt reduction campaign in 2003."
The researchers also found that some population groups were less likely to add salt at the table, including women in general,
younger age groups, people from non-white ethnic groups, those in higher income households and people living in central or
Nutritionist Dr Alan Dangour said:
"These findings indicate a need to
tailor future salt reduction efforts to specific target groups. More work is needed as a quarter of adults still add salt at the table and
salt intake levels in the UK remain well above the recommended amount of 6g per day. Eating too much salt can lead to raised blood pressure,
which increases the risk of heart disease and stroke."
Salt Consumption Linked To Moods
Research from the University of Iowa published in Physiology &
Behavior in 2009 suggests that over-consumption of and craving for salt may be explained by its mood-enhancing qualities.
Researchers found rats deficient in sodium chloride (common table salt) avoided activities they normally enjoy.
Psychologist Kim Johnson said:
"Things that normally would be pleasurable for rats didn't elicit the same degree of relish, which
leads us to believe that a salt deficit and the craving associated with it can induce one of the key symptoms
associated with depression."
The researchers explain that experiencing a loss of pleasure in normally enjoyable activities is an
important feature of psychological depression. The notion that salt may be a natural mood-elevating substance could
help explain over-consumption despite its known association with high blood pressure, heart disease and other
Previous studies have shown that the worldwide average for salt intake per individual is about 10
grams per day compared to the U.S. Food and Drug Administration recommended intake of 6 grams, and exceeding what
the body actually requires by more than 8 grams.
The researchers explain that processed and restaurant food currently contain high levels of salt
accounting for 77 per cent of daily intake. Discovery of its food-preserving properties in about 2000 B.C. was
associated with massive increases in consumption and cost. Roman soldiers' were paid in salt; the word salary
being derived from the Latin for salt. When refrigeration was introduced in the 19th century, excessive consumption
continued because people liked the taste and the cost had fallen.
The researchers conclude that the evolution of humans from creatures inhabiting salt water
environments might have played an important part in the desire for salt. Perspiration removed sodium in the
African climate. Salt was scarce because early man lived in the continental interior and relied on a
vegetable-rich diet. Nonetheless, salt is essential; sodium and chloride play a key role in transit of fluids
in and out of all cells in the body and in transmission of information via nerve cells.
Kim Johnson commented:
"Most of our biological systems require sodium to function properly, but as a species that didn't
have ready access to it, our kidneys evolved to become salt misers."
The researchers also conclude that behavior came to play a key role in ensuring the body is not deficient
in salt. Humans have evolved a taste system designed to detect salt and a brain that remembers the location of salt
sources. A pleasure mechanism in the brain is activated when salt is consumed.
However, salt also has some of the qualities of an addictive substance. For example, continued use
even when it is known to be harmful. Many people told to reduce consumption find it difficult because they like the
taste and find low-sodium foods bland. Another feature of addiction is the development of intense craving when a
drug is withheld. Researchers identified similar changes in brain activity when rats were exposed to drug or salt
Kim Johnson concluded:
"This suggests that salt need and cravings may be linked to the same brain pathways as those related to drug addiction and abuse."