Plant-based milks and yoghurts are often marketed as the obvious climate-friendly swap for dairy, but a new study suggests the real story is far more complicated — and hinges on something most shoppers never think about: fortification. Researchers compared the nutritional quality and carbon footprints of milk, yoghurt and their plant-based counterparts in France, Sweden and the United States, and found that whether a plant-based drink can genuinely stand in for milk depends less on the oat, soy or almond inside the carton and more on which vitamins and minerals manufacturers are legally required or choose to add.

The study, published in Current Research in Food Science, analyzed 168 products drawn from the official food composition databases of the three countries: 54 foods from Sweden, 56 from France and 58 from the United States. The team, led by Marta Bianchi of the Research Institutes of Sweden with colleagues from Sweden and France, deliberately excluded heterogeneous products such as flavoured milk beverages, milk desserts and condensed milk, but included flavoured yoghurts and sweetened plant-based drinks. To put the dairy aisle in context, they also ranked the products alongside 20 reference protein foods, including meat, fish, eggs and legumes, drawn from the Swedish database.

Methodologically, the work belongs to a growing field called nutritional life cycle assessment, or nLCA, which tries to answer a deceptively simple question: how much climate impact does a food generate per unit of nutrition delivered? The choice of that nutritional yardstick, known as a nutritional functional unit, turns out to matter enormously. The researchers applied two complementary indicators. The Nutrient Density Score, or NDS, averages the content of 23 beneficial nutrients — from protein and fiber to iodine, selenium and vitamin B12 — per 100 kilocalories, making it suitable for broad comparisons across food groups. The Dietary Shift Index, or DSI, is more targeted: originally built around six nutrients expected to decline when diets shift toward plant-based eating (protein, calcium, zinc and vitamins B2, B12 and D), the team modified it to include iron, a nutrient at risk when meat consumption falls.

The results exposed striking geographic differences. In France, where only 16 percent of the assessed products were fortified, milk had significantly higher nutritional quality than unsweetened plant-based milks according to the DSI, and sweetened dairy yoghurt outperformed sweetened plant-based yoghurt alternatives on both indicators. In Sweden, where 76 percent of products were fortified — largely reflecting mandatory vitamin D fortification of both dairy and plant drinks — and in the United States, where 53 percent were fortified, nutritional quality was relatively homogeneous across dairy and plant-based categories, with no statistically significant differences between them. In other words, fortification can effectively close the nutrient gap between cow’s milk and its plant-based imitators.

The country contrasts were stark in the underlying numbers. Median NDS values for unsweetened plant-based milks ranged from just 3.89 per 100 kilocalories in France to 16.52 in the United States, a more than fourfold difference driven almost entirely by added vitamins and minerals. Vitamin D was the most common fortificant in Swedish and American products, followed by calcium and vitamin B12, while American milk was frequently fortified with vitamin A as well. Notably, fortified nutrients rarely exceeded adult recommended intakes, although a few products — including French fortified milk rich in riboflavin and almond drinks high in vitamin E and calcium — surpassed them, mostly when recommendations for children were applied. A sensitivity analysis applying capping, which truncates nutrients at 100 percent of recommended values, barely changed the overall picture.

The study also tackled the perennial question of added sugar. Both the NDS and DSI capture only beneficial nutrients, so the researchers computed a separate Limiting Nutrient Index (LIM) covering saturated fat, total sugars and sodium per 100 grams. Unsweetened products generally came out ahead, with the clearest signal in Swedish yoghurts, where plain varieties scored significantly better nutritionally than sweetened or flavoured ones. Intriguingly, when the LIM was subtracted from the quality scores, the results could cut both ways: in France it levelled the difference between milk and unsweetened plant-based milks, while in Sweden it accentuated contrasts, making sweetened dairy yoghurt score lower than its plant-based counterpart. Yoghurts, both dairy and plant-based, carried the highest limiting-nutrient loads of the liquid categories, while unsweetened French plant-based yoghurt alternatives posted the lowest LIM of all.

On the climate side, the carbon footprints, drawn mainly from the French Agribalyse database and expressed per 100 grams, per 100 kilocalories and per unit of each nutritional score, confirmed the expected pattern: plant-based milks and yoghurts generally had lower median footprints than milk and yoghurt. Sweetened or flavoured plant-based milks showed the lowest category median at 0.02 kilograms of carbon dioxide equivalents per 100 grams, while unsweetened dairy yoghurt topped the range at 0.17, with individual products spanning from an almond drink at 0.01 to a chocolate-chip yoghurt at 0.51. But the magnitude of the dairy-versus-plant gap shrank when impacts were divided by nutritional quality rather than by mass or calories, and one coconut-based beverage even showed an intermediate climate impact comparable to some dairy products.

The choice of functional unit reshuffled the entire league table of protein foods. Per 100 grams, dairy and plant-based alternatives ranked below all other animal protein sources; per calorie, milk and yoghurt landed near eggs and herring; and per unit of nutritional quality, they shifted upward to align with or exceed nutrient-dense animal foods such as salmon, tuna and game. The DSI, with its narrower, transition-focused nutrient selection, consistently gave milk and several plant-based alternatives more favourable rankings than the broad NDS. Meanwhile, lentils, tofu and chickpeas kept the lowest carbon footprints no matter how the comparison was framed, and cod and game meat topped the pure nutritional rankings.

The authors are careful about the limits of their analysis. The indicators measure nutrient content but not bioavailability or the effects of the food matrix — increasingly recognized as decisive for dairy, where the fermentation of yoghurt appears to blunt the expected cardiovascular downsides of saturated fat. Iodine data were missing from the US database, potentially underestimating the quality of American products, and the climate assessment captured only greenhouse gases, leaving out water use, land occupation and biodiversity. A relatively small set of carbon footprint values had to represent a wide variety of products, and the emissions from producing fortificants themselves were not included. The inclusion of reference foods, the team stresses, was a methodological exercise, not a claim that legumes can simply be swapped for milk.

Even so, the take-home message is provocative. In countries with strong fortification traditions or mandates, plant-based alternatives can approach dairy on nutritional quality per calorie, while retaining a genuine climate advantage in most categories. Where fortification is rare, as in France, the nutritional case for keeping milk in the diet strengthens considerably. As dietary guidelines such as the Nordic Nutrition Recommendations already suggest including fortified plant drinks when milk intake is low, the study argues that fortification policy deserves the same scrutiny as the crops and livestock it influences — and that future sustainability assessments should choose their nutritional yardsticks deliberately, because the ranking of foods on the road to a climate-friendly diet depends on it.

Subject of Research: Nutritional life cycle assessment of dairy and plant-based milk and yoghurt alternatives across France, Sweden and the United States.

Article Title: Linking Nutritional Quality and Climate Impact of Dairy and Plant-Based Milk and Yogurt Alternatives: Evidence from Three Countries.

Article References: Bianchi, M., Lundmark, V., Barman, S., Hallström, E., & Bryngelsson, S. (2026). Linking Nutritional Quality and Climate Impact of Dairy and Plant-Based Milk and Yogurt Alternatives: Evidence from Three Countries.. Current Research in Food Science, Article 101598. https://doi.org/10.1016/j.crfs.2026.101598

Image Credits: AI Generated

DOI: 10.1016/j.crfs.2026.101598

Keywords: nutritional life cycle assessment, plant-based milk, dairy alternatives, fortification, carbon footprint, nutrient density, dietary shift index, sustainable diets, yoghurt, food policy, vitamin D fortification, functional unit