Butter is a common ingredient which can be used as both a delicious spread on bread and toast, and also for cooking or baking. The Consumer Council’s test on 28 samples of prepackaged butter, margarine and spreads revealed pros and cons amongst the different varieties. Although all 12 samples of butter were not detected with the toxic 3-MCPD or the genotoxic carcinogen glycidol, they had a relatively higher content of total fat, saturated fatty acids (SFAs), and trans fatty acids (TFAs), the health risks of which should not be overlooked. As for the 16 samples of margarine and spreads containing vegetable oils, they were found to have a higher average content of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) which could help in lowering “bad” cholesterol levels. However, over 80% (13 samples) were detected with the toxic 3-MCPD, while over 90% (15 samples) were found with the genotoxic carcinogen glycidol, 1 of which even exceeded the maximum level of European Union’s (EU) standard. Consumers who opt for butter should be mindful of the consumption size, so as to prevent excessive intake of SFAs and TFAs. On the other hand, when choosing margarine and spreads which have a lower fat content, consumers are reminded to try and select products with lower contaminant levels to safeguard their health.
The 28 tested samples included 12 samples of butter and 16 samples of margarine and spreads, which could be further categorised as 8 vegetable oil fat spreads, 3 blended fat spreads and blends, 2 garlic-flavoured margarines, 2 fat spreads with added plant sterols or plant stanols, and 1 shortening sample. Test items included the food safety and nutrient content, while the accuracy of the nutrient labelling was also compared.
Genotoxic Carcinogen Glycidol Level of 1 Sample Exceeded EU Standard
1 Sample Detected with Benzo[a]pyrene
During the 160°C high-temperature deodorisation process of oils, 3-MCPD esters (3-MCPDE) are formed upon reaction with chlorides. When hydrolysed in the gastrointestinal tract, 3-MCPDE would release the toxic 3-MCPD. Excessive consumption of 3-MCPD over a prolonged period would adversely affect the kidney functions, central nervous system, and male reproductive system of experimental animals. Similarly, glycidyl esters (GE) are formed during the deodorisation process of oils at over 200°C. Upon hydrolysation in the gastrointestinal tract, GE would release the genotoxic carcinogen glycidol. Therefore, consumers should reduce the intake through food as much as possible.
The test results showed that all 12 butter samples were detected with neither 3-MCPD and 3-MCPDE, nor glycidol. One of the reasons is that butter is a dairy product and is produced by churning milk or cream, thus should not contain any vegetable oils processed at high temperatures.
However, amongst the 16 samples of margarine and spreads containing vegetable oils, over 80% (13 samples) were detected with 3-MCPD at vastly varying levels. The 3-MCPD content (per kg) varied by over 14 times between the samples with the lowest (77μg) and highest (1,200μg) levels, although none exceeded the maximum levels of the EU standard.
In terms of glycidol, amongst the 16 samples of margarine and spreads containing vegetable oils, apart from 1 sample of butter and vegetable oil blended fat spread, the remaining 15 samples (94%) were all detected with glycidol at significantly disparate levels. The detected amounts (per kg) of glycidol varied by 24 times between the samples with the lowest (60μg) and highest (1,500μg) levels. The fat spread sample with the highest detected amount of glycidol even exceeded the maximum level of the EU standard (1,000μg/kg).
Over 60% (17) of the tested samples were detected with the phthalates DEHA, DEHP, DINP and/or ATBC respectively. 14 of these samples were found with DEHA, 8 with ATBC, and 1 with both DEHP and DINP, though the detected amounts of phthalates of all samples did not exceed the maximum level of the EU standard and will likely not pose health risks when consumed in regular portions.
Besides, benzo[a]pyrene (B[a]P), a type of polycyclic aromatic hydrocarbons (PAHs), is more common in fat-containing foods cooked at high temperatures. B[a]P is a genotoxic carcinogen which has been classified as “carcinogenic to human” by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO), and intake should be minimised as far as practicable. In the Council’s test, 1 sample was detected with 0.8μg/kg of B[a]P, which complied with the current action level (10μg/kg) in Hong Kong, as well as the “Harmful Substances in Food (Amendment) Regulation 2021” effective from mid-2023, which sets out a maximum concentration of 5μg/kg of B[a]P present in oil or fat or any mixture of oil and fat.
Higher “Bad” Fatty Acid Content Found in Butter
SFA Content of Margarine and Spreads Could Vary Up to 6 Times
The only sample of shortening in the current test had the highest total fat content (per 100g) amongst all samples, containing over 99.9g fat, whereas that of 1 fat spread sample was the lowest (47.6g fat), a difference of more than onefold. The Council reminds consumers that fats provide energy and essential fatty acids for the human body, and could also help the body absorb fat-soluble vitamins, yet excessive intake could lead to obesity.
Furthermore, excessive intake of SFAs could increase the levels of “bad” cholesterols in blood and impact heart health. Based on the content per 100g, the butter category had a generally higher SFA content (43.1g to 49.9g), whereas that for the butter and vegetable oil blend/blended fat spread category showed a greater variance (30.2g to 69.0g). The SFA contents for other categories were generally lower (9.5g to 32.5g). A variance of over 6 times was found between the samples with the highest (69g, 1 blend sample) and lowest (9.5g, 1 sample of fat spreads with added plant sterols or plant stanols) SFA contents.
As both artificial and natural TFAs could increase the bad cholesterol levels in the body and simultaneously lower the levels of good cholesterol, they have a greater impact on the body than SFAs. Excessive intake of TFAs over a prolonged period could increase the risks of cardiovascular disease. The TFAs in butter are naturally occurring. The TFA content (per 100g) of the tested butter samples (2.28g to 5.0g) was higher than that of the margarine and spread samples (not detected to 0.31g). As such, butter should not be consumed excessively.
Popular Breakfast Items and Delicacies with Butter Should be Consumed in Moderation
Buttered toast with ham and fried egg is a popular breakfast option for many people. However, the estimated intake of SFAs (9.9g) and TFAs (0.43g) per serving would be equivalent to 45% (SFAs) and 20% (TFAs) of the respective daily intake limits for adults recommended by the Chinese Nutrition Society. If butter is substituted with fat spread, the TFA intake could be significantly reduced. As for buttered pineapple bun, a classic Hong Kong delicacy, the SFA and TFA intake per serving cannot be undermined as they amount to 44% and 21% of the recommended daily intake limit for adults respectively. Consumers should control their consumption size to avoid increasing health risks.
MUFAs and PUFAs in food could reduce the bad cholesterol levels in the body and help lower the risks of cardiovascular diseases. Generally speaking, the average MUFA or PUFA contents of the various margarine and spread samples were higher than the butter category. Based on the MUFA content per 100g, a 17-time variance was found between the samples with the highest (34.3g, 1 fat spread sample) and the lowest (1.9g, 1 fat blend sample) MUFA content. There was an even more drastic discrepancy for PUFAs, as the variance between the samples with the highest (45.2g, 1 shortening sample used for baking) and lowest (0.2g, 1 fat blend sample) PUFA contents reached a staggering 225-fold. Despite unsaturated fatty acids (UFAs) being beneficial for health, the intake amount should still be controlled, as excessive intake could result in weight gain.
6 Samples were “High-sodium” Foods
2 Garlic-flavoured Margarines Had the Highest Average Sodium Content
Additionally, around 20% (6) of the samples reached the “high-sodium” food level (i.e. over 600mg sodium content per 100g solid food sample) according to the Centre for Food Safety’s (CFS) reference level, with the sodium content ranging from 680mg to 770mg. The garlic-flavoured margarine samples had the highest average sodium content, reaching 660mg. The WHO recommends a daily sodium intake of not more than 2,000mg (5g salt) for general adults. Based on the tested sample with the highest sodium content, consumption of 1 serving (14g) would incur a sodium intake of 108mg, equivalent to around 5% of the WHO’s recommended daily intake limit. Consumers should constantly pay heed to the sodium content of different types of food, so as to ensure that their daily sodium intake would not exceed the WHO’s recommended limit.
Half the Samples Had Huge Discrepancies Between the Labelled and Actual Nutrient Contents
Upon comparing the 28 samples’ actual nutrient contents according to the test results and that declared on their nutrition labels, 11 samples were found with discrepancies that did not comply with regulations, reflecting an unsatisfactory situation. Amongst these samples, the actual SFA content of 2 samples and TFA content of 6 samples exceeded the labelled value by over 20%, which did not comply with the tolerance limit set out in the CFS’ “Technical Guidance Notes on Nutrition Labelling and Nutrition Claims”. Besides, the TFA content of 2 samples and sodium content of 2 samples did not comply with the benchmark to be claimed as “0” on the labelling. Another 2 samples did not list out their TFA contents yet exemption was not declared on their packaging. Stressing that nutrition labelling is crucial product information, the Council urges manufacturers and agents to promptly rectify discrepancies on the product labelling as inaccurate information could mislead consumers into purchasing unsuitable food products, and might pose particularly serious impact on patients with chronic diseases, such as diabetes.
When choosing, using or consuming butter, margarine and spreads, consumers should pay heed to the following:
- As butter, spreads and margarine products are high-fat foods, consumers are recommended to reduce consumption and maintain a balanced diet;
- The butter samples, despite none being detected with 3-MCPD, 3-MCPDE or GE, were found with higher average total fat (82.1g), SFA (46.0g) and TFA (3.5g) contents per 100g than the fat spread samples;
- Although most of the fat spreads and claimed margarine samples were detected with 3-MCPD, 3-MCPDE and GE, only 1 sample’s glycidol content exceeded the EU standard, whereas the content range per 100g of total fat (47.6g to 77.6g), SFA (9.5g to 32.5g) and TFA (not detected to 0.31g) of this category was lower than that of the butter samples;
- Whether purchasing butter, spreads or claimed margarines, consumers should carefully read the product description, ingredients list and nutrition labels on the packaging and be mindful of the ingredient proportion. It is recommended to select products with lower SFA and TFA contents, and higher UFA content, especially in light of the large variance of the content between the spread samples;
- Consumers who opt for spreads should try to select products with lower contaminant levels, and be aware that they are not suitable for cooking.
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