Melamine contamination in nutritional supplements

Nutritional supplements are used in particular by competitive and recreational athletes
of all ages, and ‘weekend warriors’. The situation is further exacerbated by the general
pressure placed on certain groups to use supplements. For example, young sports participants
who are engaged in developmental and competitive phases of sport, encounter peer pressure
to use supplements. As a consequence the supplement industry has grown to meet the
increasing demands. A Global Industry Analysts Inc. report indicates that the supplement
market has not declined during the worldwide recession, but in fact exhibited steady
growth over the period 2008 to 2009. It is anticipated that the market will reach
US$93.15 billion by the year 2015. These supplements may contain adulterated substances
that may potentially have harmful short – and long-term health consequences to the
consumer 1]. Also, insufficiencies in regulation of the supplement industry increase the risk
of the nutritional supplements being contaminated. “Scrap Melamine” is an example
of a food additive/adulterant contaminant. This is composed of multi-amine and has
been used as a source of non-protein nitrogen, which falsely increases the claimed
protein content 2]–4]. Other sources and entry to humans have been via melamine resin migration to food
5], carry over from the illegal use of melamine in animal feed or feed ingredients,
and then from feed to products of animal origin 5].

A variety of effects mentioned or associated with melamine intake, although inconclusive
in humans, are, nephrolithiasis, chronic kidney inflammation, and bladder carcinoma
6]–9]. As such, melamine has been implicated in the kidney failure and or disease, and
deaths of several cats, dogs and pigs and the healthfulness of animals due to long-term
exposure of maximum melamine baseline and adulteration levels 2], 10], 11]. Humans have a risk to urolithiasis formation following long-term exposure to low
levels of melamine 12]. The pathogenic mechanism emanating via oxidative stress from increase free radical
production that cause inflammation 6]. Furthermore, it is speculated from studies in rats that renal failure occurs as
result of crystallization of ‘melamine’ in the kidney, leading to tubular cell necrosis,
regeneration, and expansion 4], 7]. The mechanism of melamine-related urinary stones formation is still unclear 9].

Melamine also causes sperm cell abnormality, without any observed evidence of genotoxicity
in prokaryotic or eukaryotic cells 2]. In humans toxicity has been reported although more specificity dose-dependent reproductive
toxicity needs to be documented 2]. Melamine is excreted predominantly in the urine and hence essentially not metabolized
in the human body although there are detectable amounts of melamine in tissue such
as liver, spleen, bladder and brain 2], 8]. Developing organs in fetus in utero and neonates ex utero are highly susceptible to the melamine accumulation 8].

The China Melamine Crisis of 2008 reports described very severe health effects in
infants and young children due to adulterated infant formula with melamine. At the
time, over 294 000 infants were screened and diagnosed with uncommon in children,
urinary tract stones and sand-like calculi associated with melamine in milk products,
of which 50 000 infants were hospitalized, and at least six associated deaths, recorded
8], 13]. This situation may have been compounded due to the frequent intake of baby formula
in early infancy, and may not provide enough time for the total clearance of the melamine
between meals, causing gradual accumulation of the contaminant inside the body 8].

Whilst the infant formula melamine scandal has since subsided, there is evidence that
melamine is ubiquitously present in the environment and the majority of the general
population, including children, are most likely still exposed 14]. Due to the urgent response needed in the face of the melamine crisis, analytical
methodology able to accurately determine this compound at trace levels became a requirement
to identify potential health risks involved with consumption of contaminated foods
consumed by humans 15]. Therefore the aim of this study was to determine whether commercially available
nutritional and traditional supplement products contain melamine (1,3,5-triazine-2,4,6-triamine),
even though the manufacturer does not declare them on the product label. A secondary
aim was to compare the content to the Tolerable Daily Intake (TDI) of melamine.