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Only Soy Milk Protein-rich Among 5 Types of Plant-based Milk 125 Cups of Coconut Milk to Achieve Calcium Content Equivalent to 1 Cup of Low-fat Milk

  • 2023.10.16

Cow’s milk is rich in protein and calcium with many health benefits, but it may not be suitable for everyone. Apart from vegans, people with lactose intolerance may have to choose plant milks as alternatives. Although there is a vast variety of plant milks, nutritionally they may not be able to completely substitute cow’s milk. The Consumer Council tested a total of 5 types of 39 prepackaged plant milk samples available on the market and referenced the Food Standards Australia New Zealand for calcium content of unfortified coconut milk. It was found that without added nutrients, coconut milk contained the lowest calcium and protein content, requiring about 125 cups and 34 cups of coconut milk respectively to achieve the same nutritional value as 1 cup of low-fat milk, while only soy milk samples had a higher average protein content among the 5 types of plant milk. In addition, despite 40% of the samples meeting the definition of high calcium, consumers are reminded that if they were to substitute cow’s milk with plant milk, they should choose products with added calcium and vitamins, as well as obtaining adequate nutrients from other dietary sources.

The Council sourced 39 samples of prepackaged plant milks, including 12 soy milks, 10 oat milks, 7 almond milks, and 5 coconut milks and 5 rice milks, with prices ranging from $1 to $8.5 per 100ml, a 7.5-fold difference between the highest and lowest priced samples. Among them, 19 received an overall rating of 4 points or above, reflecting that there are good choices regardless of price.

Soy Milk with Highest Average Protein Content

Coconut Milk and Rice Milk Least Satisfactory

Protein promotes growth and development of the body, and creates, repairs, and maintains healthy body tissues. The average protein content of the 12 soy milk samples was 3.26g per 100ml, which was much higher than the other 4 types of plant milks (0.1g to 0.66g), with the lowest average content found in coconut milk (0.1g) and rice milk (0.19g). 6 soy milk samples contained 3.4g to 4.92g of protein per 100ml, higher than that of low-fat milk (about 3.37g). Every 240ml cup of soy milk consumed would provide a protein intake of about 7.82g, which is 14.2% of the daily recommended nutrient intake for adult women recommended by the Chinese Nutrition Society. If substituted with oat milk or almond milk, it would require about 5 cups to achieve the same amount of protein as 1 cup of low-fat milk or soy milk, and for coconut milk, about 34 cups to achieve the equivalent.

In addition, protein in soy milk is a “complete protein”, i.e. it contains 9 essential amino acids that cannot be produced by human bodies, while protein in the other 4 types of plant milk is “incomplete protein”, so consumers must obtain enough essential amino acids from other dietary sources.

“High-Calcium” Plant Milks May Not Provide Sufficient Calcium Intake

According to the Food and Drugs (Composition and Labelling) Regulations, nutrient content claims for protein, vitamins, and minerals (other than sodium) can be made on the basis of the content of the relevant nutrient per 100ml of liquid food or per 100kcal of food. 16 plant milk samples met the definition of high calcium when measured per 100kcal of food. However, only 3 calcium-added samples out of the 16 were high in calcium per 100ml, including 1 soy milk, 1 almond milk and 1 coconut milk, with calcium content ranging from about 140mg to 156mg. Therefore, although some samples could be classified as high-calcium by certain definitions, and “Calcium” or “Ca” was labelled on the packaging of some samples, consumers are advised to read the calcium content on nutrition labels carefully to estimate the actual intake of calcium per serving size.

23 samples had no extra calcium added, and the calcium content of these samples ranged from 2.55mg to 76.12mg per 100ml, which was far lower than the calcium content in low-fat milk (125mg). Based on the average calcium content of samples without additions, to achieve the same amount of calcium provided by 1 cup of low-fat milk, one would need to consume about 6 cups of soy milk or 7 cups of almond milk, about 22 cups of rice milk, 33 cups of oat milk, or about 125 cups of coconut milk. Prices of coconut milk and soy milk samples were generally lower, with the average price per 100ml being $2.5 and $2.4 respectively, while oat milk was more expensive, with the cheapest sample costing nearly $3 per 100ml and the average price among samples being $3.9.

Most Coconut Milk and Rice Milk Samples Contained No Vitamin B2

Vitamin B2 helps the body convert carbohydrates, proteins, and fats in food into energy, and helps to maintain health in oral cavity, eyes, skin, hair, and nails. Vitamin B2 was not detected in 12 samples, including all coconut milks, 3 rice milks (60%), 1 almond milk and 3 oat milks. The remaining plant milks with no added vitamin B2 contained only 0.01mg to 0.035mg per 100ml, which was only 5.4% to 18.9% of the vitamin B2 content of low-fat milk (0.185mg). 2 oat milk samples with added vitamin B2 contained 0.178mg and 0.2mg respectively, which were close to the content of that in low-fat milk.

Insufficient vitamin D in the body can reduce calcium absorption ability. Vitamin D was detected in 8 samples, with levels ranging from 0.06µg to 0.865µg per 100ml. 2 coconut milk samples claimed to have added vitamin D but no detectable levels of vitamin D were found, which was inconsistent with their ingredient lists and may fail to meet consumer expectation.

Furthermore, over 60% samples showed discrepancies between labelled nutrition information and test results beyond the requirements of the Technical Guidance Notes on Nutrition Labelling and Nutrition Claims, including the calcium, vitamin B2 or vitamin D information of 13 samples, and the relevant information has been forwarded to the Centre for Food Safety for follow-up. Apart from possible errors in labelling, another reason may be due to stratification of plant milks and sediment may be deposited at the bottom of the packaging even after shaking, thus consumers may receive a nutrient intake lower than labelled values. The Council opines that manufacturers should test their products from time to time and update labels to let consumers make informed choices.

Nickel Detected in Over 60% of Soy Milk Samples

Risk is Low Under Normal Consumption

Apart from nutrient content, the tests also examined the level of metallic contaminants in the samples. Trace amounts of metallic contaminants from the environment are commonly found in foods, and soy bean and oatmeal are naturally high in nickel. Although there is currently no evidence that nickel intake poses a risk to human health, consumption of nickel-containing food may cause systemic contact dermatitis in individuals who are allergic to nickel. 10 samples were detected with nickel, including 8 soy milks and 2 oat milks, with levels ranging from 0.23mg/kg to 1.08mg/kg. For a 60kg adult, it would require consumption of 3 cups of the sample with the highest nickel level to reach the tolerable daily intake (TDI) of 0.78mg.

In conclusion, consumers wishing to replace cow’s milk with plant milk should examine nutrition labels carefully and choose a fortified product according to their body’s intake needs, while at the same time obtain adequate protein, calcium, and different vitamins from other dietary sources. Consumers should pay attention to the following when purchasing and consuming plant milk:

  • If “calcium”, “calcium carbonate”, “calcium phosphate”, “tricalcium phosphate” are indicated in the ingredient list, it means that the product is added with calcium; if labelled with “vitamin B2”, “riboflavin”, it means the product is added with vitamin B2; and if “vitamin D”, “vitamin D2”, “vitamin D3” are listed on the label, it means the product is added with vitamin D;
  • Individuals allergic to soy beans, gluten, almonds or other nuts should scrutinise the ingredient list and allergen information on the packaging;
  • Breastmilk and formula milk contain essential nutrients for the growth of infants. Even if their baby is lactose intolerant, parents should not substitute with plant milks without guidance, but instead consult a doctor or registered dietitian beforehand;
  • Excessive intake of caffeine increases the urinary excretion of calcium, whereas foods or drinks containing oxalic acid reduces calcium absorption. Consumers should avoid simultaneously consuming foods or drinks containing calcium and oxalic acid, as well as excessive consumption of coffee, strong tea, and energy drinks.


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