MERELY - from "nectar of the gods" to honey toxicity?
– myth and reality (2)

Dr. Mirela Stranț, Cluj Napoca,

doctor with apiphytotherapy competence,

Ayurveda lecturer AMN-Romania

Comparison of HMF levels in honey with other food products

As we already know HMF is not naturally present in food but is formed by heat treatment and in combination with other factors and there is no fixed concentration of HMF in different foods. Baking temperature, rate of sucrose degradation, concentration of reducing sugars, type of sugar (glucose, fructose or others), water activity, addition of other food additives such as HMF-containing sweeteners, colouring agents, caramelisation, storage time and temperature, type of storage and metal processing vary greatly between different food products. Therefore, the HMF content varies from food products even between those of the same type.

However, honey is a safer food than other processed foods in terms of its HMF concentration.

Floral honey and apple honey processed at 95°C for 90 min and at 90°C for 75 min showed HMF levels below 40 mg/kg. In contrast to honey, when processing other foodstuffs at relatively higher temperatures (during baking, roasting), longer times and different additives are required, which profoundly affect the HMF content of the food.

For example, cakes baked at temperatures above 200°C accumulate drastically, 10-100 times more HMF (167.4-1100.1 mg/kg) than cakes baked below 200°C (9.9-39.6 mg/kg).

S-reported that fresh cakes baked at 300°C and with sugar added during processing contain up to 1100 mg/kg HMF. Even the addition of ammonium bicarbonate can dramatically increase the HMF content (over 3500 mg/kg) in cakes containing sucrose baked at 220°C. Thus, HMF formation is unavoidable and comparison or classification of foodstuffs with respect to HMF concentration cannot be performed accurately.

Health effects of HMF. Studies and conclusions.

Since we have developed the subject of hydroxymethylsulfural (HMF for short) so much, let's also look at its effects on us. In many studies s-found that HMF has negative effects on human health, such as cytotoxicity to mucosa, skin and upper respiratory tract, mutagenic effects, chromosomal aberrations and oncogenicity in both animals and humans as well as inhibition of some enzymes. However, in more recent studies, HMF s-has also been shown to have a range of positive effects, such as antioxidant, anti-allergic, anti-inflammatory, anti-hypoxic or excess uric acid depletion.

For example, oral administration to mice of single doses of 900 or 1300 mg/kg showed significant damage to DNA-of kidney cells. Preclinical and inice confirmed that 5-HMF causes chromosomal aberrations. Orally administered HMF is converted to reactive SMF (a metabolite of HMF) after it has been absorbed through the gastrointestinal tract.intestinal excretion that is not immediately excreted in the urine due to renal reabsorption, thus allowing SMF to accumulate in the plasma and making itl available to react with cellular proteins and DNA-ul. In preHMF and its derivative SMF is a clinicalhave been confirmed to be carcinogenic. At a daily oral dose of 500 mg/kgbody mice developed numerous adenomatous intestinal foci, but other researchers conducting the same experiment were unable to induce intestinal tumours with HMF.

In topical application of sulphoxymethyl (SMF) and chloromethyl derivatives of HMF, s-found that mice develop papillomas on their skin.Another derivative of HMF, 5-Chloromurfural, has been found to induce hepatocarcinoma in male rats. However, we cannot fail to note that s-used pure HMF daily in doses hundreds of times the safe dose. In contrast to these studies, a study by Zhao et al indicated that HMF can induce apoptosis of cells with DNA, with anticarcinogenic.

HMF is reported to have cytotoxic effects at high concentrations, as the compound causes irritation to mucous membranes, skin, eyes and upper respiratory tract. Its metabolite, SMF s-has been shown to be a potent nephrotoxic agent inan in vivo study in which male mice wereadministered intraperitoneally a huge dose of SMF (250 mg/kg). After 5-11 days posttreatment, the mice died or became moribund, possibly due to liver damage or more severe kidney damage. Another ex vivo study indicated that HMF decreased cellular glutathione levels (glutathione is a potent antioxidant produced in the liver).

However, there appear to be positive health effects. Some studies show antioxidant effects of HMF, by counteracting free radicals.

Some studies also show that HMF has a protective effect on hepatocytes damaged by hydrogen peroxide (H2O2). Other research shows that administered in small amounts, HMF can increase survival under hypobaric hypoxic conditions and could be a potent therapeutic agent against acute mountain sickness, high altitude cerebral oedema and high altitude pulmonary oedema, significantly attenuating the degree of hypobaric hypoxia-induced permeability of the blood-brain and the degree of neuronal damage in the CA1 region of the hippocampus. HMF also has an anti-allergic effect by blocking histamine release and Ca2+ signalling through free radical neutralising activity.

As we can see, some studies have different and even opposite results. Certainly the results depend on the approach (studies on human or animal cells carried out in the laboratory, in vivo studies on animals and humans), oral administration, by injection, infusion or topical application, small, medium, large or huge doses and last but not least administration of a single compound, extracted from the "context", i.e. the food from which it comes.

The situation becomes even more complex when we also consider the particularities of the body exposed to large amounts of HMF. Many studies have revealed that different cells respond differently to HMF-induced cytotoxicity. The sensitivity of cells to HMF depends on the presence and expression levels of receptors for metabolism, structure and enzyme activity.

At the preclinical level, no s-observed toxic effects at daily doses between 80 and 100 mg/kg body weight. This means that a 70 kg man would have to consume over 150 kg of heat-treated honey to get sick, which is absurd. The 6-7 grams of honey from the hot tea or a few dozen grams ina cookie sheet doesn't justify worrying about so-so-called toxic effects of honey. And while we're on the subject of honey cakes, a lot more HMF is produced from the flour or milk used to make them.

Zaitzev and collaborators established a safe daily dose of 132 mg/day for HMF using a 40-fold safety margin. Importantly, in humans, both HMF and its metabolites are completely excreted in the urine within 48 hours after oral administration of 240 mg/day (much higher than the safe dose).

Conclusion

As a component of processed foods, HMF has both adverse and beneficial effects on human and bee health. Some effects of HMF on human health and its carcinogenic as well as anticarcinogenicity remain inconclusive, with many studies only conducted at the preclinical level.

Beyond all this, on an individual level, we must use our common sense, but we must not neglect information that can be extremely useful. Heat-treated honey is certainly not the best option when we want to benefit from all its exceptional therapeutic properties, some of which I have already mentioned.

If we are looking for curative or regenerative effects, we will use raw, unheated honey which we will not subject to thermal processes. If, for example, we drink herbal tea for a cold or cough, we prefer to let the tea cool down before adding honey. In this way we will benefit fully from the naturally occurring enzymes in honey, the antimicrobial, antioxidant, anti-inflammatory and expectorant factors, and on the other hand we will not irritate the already sore throat with a very hot liquid.

If we want to use it as a sweetener for hot liquids or healthy sweets (not those with white flour, refined oil, margarines, pasteurized or powdered milk, additives, colorings, etc.), we can use it as a sweetener. which themselves have multiple adverse health effects), we can do so without the aberrant fear that we will develop some serious and threatening disease.

In addition, as mentioned above, it is good to have a varied, balanced diet, without excesses, consisting of whole foods and as little processed as possible and with a higher intake of raw foods.

In this way we will have a lower intake of hydroxymethylsulfural, we will avoid many other more harmful substances but above all we will bring a significant intake of nutrients and substances with a protective role. This will help us to have a healthy, harmonious body and flourishing health.