High consumption of fructose in the diet may lead to spatial memory problems, according to a new study with rats from Georgia State University.

Rodents fed a diet where fructose represented 60 per cent of calories ingested during the day were found to perform poorly in tests of memory, compared to rodents fed a control diet, say findings in the journal Neurobiology of Learning and Memory.

The researchers, led by Marise Parent, suggest their findings are relevant to humans, and nod towards the use of fructose-containing sweeteners used by the food industry. Table sugar (sucrose) contains 50 per cent fructose and 50 per cent glucose, while high-fructose corn syrup (HFCS 55) contains 55 per cent fructose and 42 per cent glucose.

“Fructose, in many forms, is added to countless foods including carbonated beverages, fruit products, baked goods, cereals, and dairy products,” wrote lead author Amy Ross. “Indeed, North Americans would be greatly challenged to purchase processed foods not containing some form of fructose.”

Commenting on the applicability of the results to humans, Ross and her co-workers noted: “Although deriving 60 per cent of calories from fructose produces pathology in rodents that is similar to that experienced by humans, the level consumed is outside the current range of the human diet.

“Notably, determining what concentration would be comparable between humans and rats is difficult, given that a rat is expected to metabolize fructose at a different rate than a human and because rats typically require higher doses of drugs than humans to observe an effect.”

Study details

Parent and her research team divided Sprague-Dawley rats into two groups, one fed a diet where fructose represented 60 per cent of calories ingested during the day, and the other was fed standard rat chow containing 60 per cent vegetable starch.

“Rats are an excellent animal model to study the effects of fructose intake because their metabolism of fructose closely resembles that of humans,” explained the researchers. “The present research focused on male rats, given that men are the greatest consumers of fructose.”

The rats were placed in a pool of water to test their ability to learn to find a submerged platform, which allowed them to get out of the water. Two days later, the animals were returned to the pool with no platform present to see if the rats could remember to swim to the platform’s location.

“What we discovered is that the fructose diet doesn’t affect their ability to learn,” said Parent. “But they can’t seem to remember as well where the platform was when you take it away. They swam more randomly than rats fed a control diet.”

Commenting on a potential mechanism, the researchers note that fructose, unlike glucose, is processed almost exclusively by the liver, and produces an excessive amount of triglycerides, which may interfere with insulin signaling in the brain, and affect the brain’s ability to adapt based on new experiences.

Results were similar in adolescent rats, added Parent, but it is unclear whether the effects of high fructose consumption are permanent.

“The bottom line is that we were meant to have an apple a day as our source of fructose,” said Parent said. “And now, we have fructose in almost everything.”

Research is ongoing in Parent’s lab with current research looking at the intake of fish oil on triglycerides increases and memory deficits.

The Codex Alimentarius Commission (CAC) concluded a week-long meeting and adopted more than 30 new international standards, codes of practice and guidelines to improve worldwide food safety and protect the health of consumers.

New standards adopted by the Commission include:

Reduction of acrylamide in food

The Commission approved measures for reducing the formation of acrylamide in food. The code of practice will provide national and local authorities, manufacturers and others with guidance to prevent and reduce formation of acrylamide in potato products during all phases of the production process. The guidance includes strategies for raw materials, the addition of other ingredients; and food processing and heating. The chemical acrylamide, first identified in food in 2002, is produced during frying, roasting and baking of carbohydrate-rich food such as French fries, potato crisps, coffee, biscuits, pastries and breads. Acrylamide is considered a possible human carcinogen.
Reduction of contamination with polycyclic aromatic hydrocarbons.

The Commission adopted the first guidelines for reducing polycyclic aromatic hydrocarbons (PAH) intake through final food preparation. Because smoking and direct drying processes are used both in industry and in private households, the guidance can also form the basis of consumer education programmes. Parts of PAH are possible human carcinogens formed during the combustion of fuel both in the smoking and in the direct drying processes involved in the preparation of food.

Prevention of Ochratoxin A contamination in coffee

The Commission adopted guidance to enable coffee-producing countries to develop and implement their own national programmes for the prevention and reduction of Ochratoxin A (OTA) contamination. OTA is a fungal toxin also considered a possible human carcinogen.
Powdered follow-up formulae

The Commission adopted criteria for salmonella and other bacteria in powdered follow-up formulae for children six months of age or older and for special medical purposes for young children. A bacterium of special concern is E. sakazakii, for which Codex adopted specific criteria for powdered formula for infants (0 to 6 months) in 2008. The Commission decided that in countries with particular risk for E. sakazakii from consumption of follow-up formulae (i.e. countries with substantial populations of immunocompromised babies) similar criteria for E. sakazakii could be introduced for follow-up formula as for powdered formula for infants.

Follow-up formulae should only be used for the intended target population. Unfortunately, they are often consumed by babies younger than six months of age. The standard stresses the need to address such product misuse issues through education campaigns and training.

Listeria monocytogenes in ready-to-eat food

The Commission adopted parameters for microbiological testing and environmental monitoring for Listeria monocytogenes in ready-to-eat food. A maximum level was set for certain food products where the bacteria cannot grow, while in ready-to-eat products where growth is possible, no Listeria monocytogenes will be allowed. The parameters will help producers control and prevent contamination of ready-to-eat foods with this bacterium that can result in listeriosis, a potentially fatal disease. While healthy people rarely contract listeriosis, it can cause miscarriages and stillbirths, as well as serious and sometimes fatal infections in those with weakened immune systems, such as infants, the elderly and persons with HIV infection or undergoing chemotherapy.

The Commission also adopted regional standards for ginseng products, fermented soybean paste and gochujang.

“The standards and guidelines adopted this week will make a positive impact on the lives of people around the world,” said CAC Chairperson Karen Hulebak. “The Commission is working faster than ever before to address the most pressing food safety challenges we face.”

Ezzeddine Boutrif, FAO Director, Nutrition and Consumer Protection Division, noted that Codex membership now represents 99% of the world’s population. “Applying Codex standards and guidelines are an important part of ensuring that consumers in every part of the world can be protected from unsafe food,” he said.

The Commission also launched new work projects, among them establishing maximum levels for melamine in food and feed. In the last few years, high levels of melamine have been added illegally to food and feed products, causing illness and death. Because it has many industrial uses, melamine may be found in trace amounts in the food chain due to its presence in the environment. Setting maximum limits will help governments differentiate between unavoidable melamine occurrence and the deliberate adulteration of food and feed.

Other new work proposals adopted by the Commission include:

• principles and guidelines to assist governments in the development and operation of comprehensive national food control systems that protect the health of consumers and ensure fair practices in the food trade;
• practices to control viruses in food, especially noroviruses (NoV) and hepatitis A (HAV) in fresh produce, mulluscan shell fish and ready-to-eat food;
• prevention of aflatoxin (toxic substances produced by moulds and known to cause cancer in animals) contamination of Brazil nuts; and
• setting maximum levels and defining sampling plans for Fumonisins, (toxic substances produced by fungi) in maize and maize products.

“We welcome the participation of more developing countries in the meeting this year which reflects global awareness of food safety issue and the impact of Codex Trust Fund,” said Dr Jørgen Schlundt, Director of WHO’s Department of Food Safety and Zoonoses.

Approximately 500 people, representing 125 countries, participated in the Commission meetings. Karen Hulebak of the United States of America was re-elected Chairperson; Knud Østergaard of Denmark, Sanjay Dave of India and Ben Manyindo of Nigeria were re-elected Vice-Chairpersons.

The European Food Safety Authority (EFSA) has rejected three article 13.5 probiotic and prebiotic health claims and one article 14 claim linking prebiotics with a range of benefits from immunity to diarrhoea for failing to demonstrate causality.

EFSA’s Panel on Dietetic Products, Nutrition and Allergies (NDA) rejected one emerging science, article 13.5 claim from Sunstar Suisse linking p Lactobacilllus reuteri-fortified, probiotic chewing gum and tablets and oral health.

Italy-based Sunstar Suisse proposed the claim: “Gum Periobalance, combined with a correct oral hygiene, helps re-balancing the oral microflora and improving oral health.”

But the NDA said while decreasing the levels of mutans streptococci in the oral cavity and reducing the amount of dental plaque may be beneficial to health, the dossier did not demonstrate how the product in question, Gum Periobalance, helped this to be so.

The dossier contained two published human intervention studies and one unpublished in vitro study, all of which were found wanting for lack of relevance to the claimed effect or lack of demonstrated causality.

Probiotic supplements

Three prebiotic submissions from UK-based Clasado Limited also drew negative opinions from the scientific assessor for similar reasons.

Clasado submitted three claims for a prebiotic supplement, Bimuno, that contained a β-galacto-oligosaccharide mixture.

Two article 13.5 claims proposed gut health and immunity benefits, while an article 14 disease reduction claim linked the supplement with traveller’s diarrhoea.

Gut health

For the gut health claim, the NDA dismissed three human intervention trials and 11 non-human trials submitted by Clasado it hoped would back its claim that the supplement could improve “gastrointestinal function”. Reasons included lack of power, use of old formulations, non-matching formulations (between trial and product in question).

Clasado proposed the claim: “Bimuno (BGOS) Prebiotic selectively stimulates and increases the number of bifidobacteria in the gut of regular consumers. Bifidobacteria are recognised as health promoting bacteria that support the general well-being of the host.”

While some bifidogenic effects were detected at doses between 2.75g/d and 5.5 g/d, the NDA said this did not translate into a health benefit.

“The results do not show that the changes in the number of bifidobacteria are beneficial for the gut function,” it concluded.

Immunity

For the article 13.5 immunity claim, Clasado proposed the following health relationship: “Bimuno (BGOS) Prebiotic supports the immune system by helping to increase the natural killer cell and phagocyte activity in regular consumers. Natural killer cell activity and leukocyte phagocyte activity both play a key role in the function of the immune system.”

Its simplified claim read: “Supports your natural defences” and was intended for elderly people who consumed 5.5g of Bimuno Prebiotic per day for at least 10 weeks.

The NDA considered that only one clinical trial involving 44 elderly people, was relevant but found it wanting as it dod not, “provide any evidence that the observed changes in counts of faecal bifidobacteria, NK cell activity, production of inflammatory cytokines and phagocytosis activity constitute beneficial changes in the immune system”.

Traveller’s diarrhoea

Clasado’s article 14 disease-reduction claim stated: “Regular consumption of Bimuno (BGOS) Prebiotic helps to protect against the bad bacteria that can cause travellers’ diarrhoea.”

But again the NDA said the claim at a level of 5.5g per day was not substantiated by an unpublished, human clinical trial, an unpublished animal study, three in vitro studies and one review.

The three in vitro and review were deemed irrelevant because were not specifically testing or referring to Bimuno.

The clinical trial was deemed insufficient because of a number of flaws including a high drop-out rate, insufficiently characterised population, lack of data risk factors and insufficient description of statistical analyses.

More than 4000 claims are due to be processe under the 2006 nutrition and health claims regulation by the end of January, 2010, although the European Commission has admitted it is unlikely this deadline will be met.