Phosphorus additives pose ‘hidden’ danger to kidney patients
Source of Article: http://www.foodnavigator.com/Science-Nutrition/Phosphorus-additives-pose-hidden-danger-to-kidney-patients
By Stephen Daniells,
11-Feb-2009
Patients
with kidney disease may be at danger from a ‘hidden threat’ of phosphorous
additives found in processed and fast foods, says a new study from the US .
Writing in the new
issue of the Journal of the American Medical Association (JAMA),
Ohio-based scientists report that additional phosphorous, such as sodium
phosphate or pyrophosphate, may be too much for a compromised kidney to
expel.
The additives
are used to enhance flavour and shelf life, particularly in meats, cheeses,
baked goods, and beverages, said the researchers from
Certain foods, such as
meats, dairy products, whole grains, and nuts, naturally contain high levels
of phosphorous, and patients with advanced kidney disease
are recommended to avoid these foods. Increased levels of the mineral in the
blood can lead to heart disease, bone disease, and may even be fatal for
patients with advanced kidney disease.
"Phosphorus is
already abundant in naturally-occurring foods," explained
co-researcher Srilekha Sayre. "By adding
even more phosphorus to our food supply, we may be exceeding the body's
regulatory ability, especially for those with kidney disease.
“We need to limit the
use of these additives until their impact is better understood or at least
encourage the Food and Drug Administration to require food manufacturers to
report phosphorus content on nutrition food labels."
Study details
The Ohio-based
researchers randomly assigned 279 people with advanced kidney disease
receiving dialysis treatment to one of two groups: One group acted as the
control, and received usual care. The second group was taught to avoid additive-containing
foods when purchasing groceries or eating at fast food restaurants. At the
start of the study, all of the participants had high phosphorus blood levels,
defined as at least 5.5 milligrams of phosphorous
per decilitre.
Three months later the
researchers found that the blood levels of phosphorus in the intervention
group had decreased by two and a half times more than in the control group
(0.4 versus 1.0 mg/dL, repsectively).
“The 0.6 mg/dL larger decline in average phosphorus level among
intervention participants compared with control participants corresponds to a
5 to 15 per cent reduction in relative mortality risk in observational
studies,” wrote the researchers.
“Our intervention has
the advantages of being simple, low-cost, and easy to implement.”
Policy implications
The researchers said
that the results have implications for manufacturers and policy makers. The
latter should consider both the cost of policy approaches to address the
problem of phosphate additives in foods, and the related health care costs
associated with high phosphorus intake and hyperphosphatemia.
“Policy approaches may
include mandating that phosphorus content be listed on nutrition facts labels
(as calories, fat, and sodium already are),” wrote the researchers. “Although
manufacturers may voluntarily include phosphorus content on such labels, most
foods do not have this information.”
“It is worth noting
that many manufacturers eliminated or greatly reduced the trans fat content
of their products in response to a recent mandate to include trans fat on
nutrition facts labels. Other approaches may involve creating incentives for
producing and marketing low-phosphorus products and funding alternatives to
phosphorus-containing additives.”
Source: Journal of
the American Medical Association
Volume 301, Issue 6, Pages 629-635
“Effect of Food Additives on Hyperphosphatemia
Among Patients With End-stage Renal Disease: A Randomized Controlled Trial”
Authors: C. Sullivan, S.S. Sayre, J.B. Leon, R. Machekano,
T.E. Love, D. Porter, M. Marbury, A.R. Sehgal