The Norwegian Scientific Committee for Food Safety (VKM) suggests a tentative upper limit for supplemental beta-carotene of 4 milligram per day. This is the conclusion in a risk assessment of beta-carotene in supplements carried out by VKM on the request of the Norwegian Food Safety Authority.
Beta-carotene is one of many carotenoids found in plants, fungi and bacteria. It is also used in many types of food supplements. Beta-carotene can be converted to vitamin A in the body and is found naturally in for example carrots. Carrots contribute to approximately half of the total beta-carotene intake in the Norwegian diet, followed by mixed frozen vegetables, tomatoes, fruits and berries.
VKM emphasises that this opinion do not addresses regular food such as vegetables and fruit but supplemental beta-carotene only.
The large Finnish ATCB study (Alpha-Tocopherol, Beta-Carotene Cancer Prevention-study) showed that the risk of lung cancer among smokers who took food supplements with beta-carotene increased. The study included smokers only. Also a Danish study showed an increased risk of cancer among smokers taking beta-carotene supplements.
Four meta-analyses have also shown an increased risk of death among the groups receiving supplemental beta-carotene.
The four meta-analyses on mortality all found a 6-7% increased risk of death, but the increased mortality may be explained by the findings in the Finnish study. One possible reason for the increased risk of lung cancer is that beta-carotene might have a negative prooxidative effect instead of a positive antioxidative effect in the cells on the tissue surface of the lungs in smokers.
The scientific literature that VKM has evaluated showed no increased risk of other types of cancer than lung cancer.
In VKM's opinion it can not be ruled out that the risk of lung cancer may also increase in people with chronic inflammation conditions in the lungs. This includes individuals with asthma and COPD.
VKM concludes that beta-carotene from regular food such as vegetables and fruits do not pose a health risks. On the contrary, all scientific research shows that high intake of fruits and vegetables protects against various types of cancers and a variety of other diseases.
There is no upper tolerable limit (UL) for beta-carotene. VKM suggests a tentative upper limit for supplemental beta-carotene of 4 milligram per day.
The uncertainty related to the data for determining a tentative UL is described in detail in the report.
In 2006, the European Commission initiated work to set common limits for vitamins and minerals. The work was temporarily put on standstill in 2009.
Pending establishment of common maximums limits in the EU, the Norwegian Food Safety Authority is evaluating the national maximum limits for vitamins and minerals in food supplements.
The VKM Panel on Nutrition, Dietetic Products, Novel Food and Allergy has been responsible for the risk assessment.