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Institute of Food Chain Science

Department of Digital Food Science

Dietary supplements with herbal active ingredients
The following information is provided on recently identified herbal active substances used as ingredients in food supplements that pose a potential risk.

Dietary supplements contain nutrients or active substances in a concentrated form and are intended to supplement the traditional diet.

Emerging Risk Exchange Network of EFSA has received several issues regarding food supplements containing active ingredients with adverse health effects.

The use of vitamins and minerals is well regulated. However, in most of the cases, there are no legally permitted maximum levels for the assessment of other active substances with a physiological effect (e.g. herbal active substances).

In Hungary, there is a so-called negative list of plants, plant parts and active substances that are not regulated for their use in food supplements, but whose use should be restricted because of their effects on the human body, according to the literature. The list is under continuous review.

It is important to point out that if a plant is not on this list, it does not mean that it can automatically be used in food supplements. Many dietary supplements containing herbal active substances are appearing on the market in the hope of making a profit, taking advantage of new trends favouring health-conscious, natural ingredients. They often contain herbal active substances not yet evaluated from a health point of view, or active ingredients above the safe dose level.

The following information is provided on recently identified herbal active substances used as ingredients in food supplements that pose a potential risk.

Dietary supplements with green tea extract

Mostly recommended for weight loss and weight control, although these health claims are not supported by EFSA.

The extracts contain EGCG (epigallocatechin-3-gallate) in a very high dose with hepatotoxic effects and there were several reported liver damage and consequential death cases related to the consumption of green tea extract containing dietary supplements.

The content of EGCG in traditionally prepared green tea infusion is approx. 77 mg per 100 ml while some of the food supplements containing green tea extracts, marketed in the Nordic countries provide up to 980 mg EGCG per day (based on the recommended daily dose as stated on the product). Mean and 95th percentile of EGCG intake from green tea infusions in Germany was calculated to be 95-148 mg and 289-448 mg, respectively. According to the safety assessment carried out by the Norwegian Institute for Public Health (NIPH) green tea extracts have been implicated in many cases of clinically apparent acute liver injury, including instances of acute liver failure and death.

France and Belgium have drafted national provisions and guidelines specifically for the use of green tea extracts in food supplements. Both countries have specified the solvents that may be used to prepare green tea extracts and have also set limits on the maximum daily dose based on the extracts EGCG content. While France limits the daily dose for EGCG at 300 mg/day, Belgium has set this level at 600 mg/day.

References:

Seaweed as dietary supplement or functional food/food ingredient/food additive

Seaweeds are mainly available in the form of dietary supplements (powder or tablets), but their use as functional food, food ingredients, additives and feed are also increasing. Seaweeds are macroscopic, multicellular marine algae that usually live attached to rocks or any hard substrates. Although the consumption of seaweed is limited in most western countries, the growing perception that seaweed is a "healthy food" (high in protein, fibre and trace elements) may lead to increased demand for mass production.

Potential risks associated to the consumption of seaweed:

  • Iodine: following certain diets that encourage algae consumption can lead to excessive iodine intake, which may lead to thyroid disorders.
  • Although in Europe the level of arsenic in drinking water is on average low, some food products (e.g. rice and seaweed) are imported from all over the world including from regions with naturally high arsenic levels.
  • Metal pollution: metals can be introduced into food chains via bioaccumulation in primary producers (e.g. seaweed), and may potentially lead to toxic effects.
  • Viruses: In February 2012, the first norovirus outbreak of gastroenteritis associated with green seaweed was reported.
  • Certain epiphytic microalgae, in particular dinoflagellates producing toxins that can be isolated from macroalgae. Some species of cyanobacteria (also referred to as blue-green algae) can produce toxins (hepatotoxins, neurotoxins, cytotoxins, dermatotoxins, irritant toxins) contaminating the seaweed.

Recognising the risks and the seriousness of the threat, there are several research, data collection and risk assessment ongoing on algae consumption.

References:

Dietary supplements containing piperine

Piperine is the major alkaloid present in fruit of black pepper (Piper nigrum L.). Various pharmacological activities have been attributed to piperine, namely anti-inflammatory, anti-microbial, gamma-aminobutyric acid (GABA) modulator and as preventive of neurodegenerative diseases. It increases the bioavailability of drug active ingredients.

Piperine is also an antioxidant, affects lipid metabolism in several ways. It has been implicated in the treatment of obesity, along with other alkaloids. The health claims made about piperine are unfounded.

According to EFSA's evaluation, piperine is safe for consumption when using it as a food seasoning, however, dietary supplements contain much higher dose. EFSA has identified the need for a risk assessment of consumption at extreme concentrations for average and high consumers and for long-term consumption.

References:

Aloe vera in dietary supplements, foods

The consumption of Aloe vera and aloe vera extracts has been attributed to a number of positive effects (e.g. anti-Parkinson's disease, support of intestinal, liver and nervous functions, weight control, collagen and elastin production, anti-inflammatory effects, energizing effects), which is why its use as an extract in dietary supplements and as a food, e.g. in the form of soft drinks, is becoming increasingly common.

Aloe vera and other Aloe species (Aloe ferox, Aloe arborescens) may contain aloin, which has potential adverse health effects. Research suggests that it may cause kidney and liver damage, and cases of acute hepatitis have been associated with its consumption. The aloin content of foods depends on several factors, most notably the processing methods of the plant.

In Hungary, Aloe vera and other Aloe species are not recommended for use in food supplements and other food fortified with other substances, however, the gel extracted from the leaves may be used, while maintaining the sub-limits of 0,1 mg/kg as established by the Scientific Advisory Committee.

References:

Diosmin and hesperidin in dietary supplements

These active ingredients are flavonoids of citrus fruits which are used basically in medications for venous diseases. The EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) concluded that a cause-and-effect relationship has not been established between the consumption of a combination of diosmin, troxerutin and hesperidin and the maintenance of normal venous-capillary permeability.

The use in dietary supplements is more and more common. There is less knowledge on their effects, which can possibly be mutagenic and carcinogenic. Further research and risk assessment are needed.

References:

Berberine in dietary supplements

Bioactive alkaloid of Berberis vulgaris.

Berberine-containing plants are used in food supplements primarily to positively effect metabolic diseases, cardiovascular diseases, inflammations, tumours, although no health claims are authorised at European level.

Barberry is approved for consumption in small amounts as a food (EFSA). However, it is also included in the list of herbal active substances of concern for human consumption.

The active substance interacts with many drugs and there are insufficient toxicological data (e.g. on the minimum dose that can induce an effect), thus its consumption is not recommended for vulnerable groups (e.g. pregnant women, children, elderly).

In Hungary, all berberine-containing plants are also included in the negative list, which states that the indication or method of administration does not correspond to the intended use of the food supplement. Nevertheless, food supplements containing berberine are still available on the domestic market.

References:

Moringa leaves in dietary supplements

Moringa tree is native to Asia and Africa. The fruits, flowers and leaves of the tree are an excellent source of vitamins and minerals. Moringa leaves have many beneficial effects, such as general health benefits, antioxidant, anti-ageing, anti-inflammatory, detoxifying, blood sugar regulation, etc.

EFSA cannot conclude whether African Moringa may pose a risk for human consumption and raises safety objections to the decision to place African Moringa on the EU market as traditional food.

According to studies identified by EFSA, moringa leaves (both Moringa stenopetala and Moringa oleifera) may contain glucosinolates, cyanoglycosides, phytates and tannins. Animal and human experiments suggest that consumption of moringa leaves may have effects on thyroid function and liver enzymes, and that an extract (ethanol) from the leaves may have contraceptive or abortifacient effects. EFSA is of the opinion that the exact amount of these compounds in moringa leaf powder is not known and there are no adequate exposure assessment calculations available. There is also insufficient information on the possible occurrence of other undesirable substances in the powder and their levels.

In Hungary, dried leaves, capsules and powders are also available, both on their own and in the form of tea mixtures. Moringa is not on the list of prohibited plants. EFSA's opinion is that further toxicological testing and risk assessment is be needed.

References:

Adulteration

The removal of the pre-market authorisation procedure has led to a high level of abuse of dietary supplements. Food supplements are often marketed as consisting of natural ingredients, but they contain active pharmaceutical ingredients to achieve the promised effect. Benzodiazepines in sleep aids; sibutramine, fenfluramine in weight loss products; sildenafil, tadalafil, vardenafil for erectile disfunctions; androgen steroids for increasing muscle mass are often used in dietary supplements.

The issue of adulterated food supplements containing active pharmaceutical ingredients creates a particular legal anomaly, given that food supplements and medicines are regulated differently, so it is questionable which legislation applies in the case of health damage.

EU ambitions

The European Food Safety Authority (EFSA) Emerging Risk Exchange Network (EREN), a network of Member State experts, has proposed several initiatives on food supplements, recognising the complexity and seriousness of the problem. These include monitoring of relevant legislation, monitoring of herbal active substances, monitoring of activities related to dietary supplements, monitoring of factors (e.g. social media, online marketing) that have an impact on this area.

It is considered important to share data and information (consumption data, information on health concerns, marketing data, etc.) between Member States, where sufficient quantity and quality of data is available, and a risk assessment can be made for each herbal active substance following prioritisation between several cases. The general aim is also to develop a targeted risk communication strategy on the subject.

Problems with intervention options

The powerful impact of social media provides a new space for the dietary supplements market, but the possibilities for intervention vary at Member State level, for example public authorities often do not have the possibility to shop online in case of suspected counterfeiting of products sold on the internet. Portugal has launched a project specifically to detect banned ingredients in dietary supplements bought online.

The situation is made more difficult by the fact that often only the packaging or the name is changed during marketing, so that products that have been withdrawn can be put back on the market.

Given that this legal environment does not provide sufficient consumer safety, due caution is needed in the use of food supplements. The regular consumption of irresponsible, uncontrolled, non-medically recommended dietary supplements poses serious risks due to the presence and effects of biologically active substances.

There are so many dietary supplements on the market today that it is essential that key players in the health sector (doctors, dieticians, pharmacists) have the right knowledge and that these products can become a real tool for achieving a healthy lifestyle, complementing a varied diet. It would also be important to carry out expert monitoring of the media to check the truthfulness of claims made in commercial advertising.

Useful information

A list of the notified food supplements and the products affected by the market surveillance measures in Hungary (withdrawal from the market, suspension of marketing) can be found here.

Important information on dietary supplements is available in Hungarian on the OGYÉI website.

Also in Hungarian, information on the toxicity and side effects of poisonous and medicinal plants and their active substances, as well as information on herbal poisoning and adverse effects of herbal products, is available from the Országos Kémiai Biztonsági Intézet Egészségügyi Toxikológiai Tájékoztató Szolgálat (Health Toxicology Information Service of the National Institute for Chemical Safety).

ESCO report: Advice on the EFSA guidance document for the safety assessment of botanicals and botanical preparations intended for use as food supplements, based on real case studies 

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