Oat Milk vs Soy Milk: A Dietitian Compares Them!

As a registered dietitian, I understand the importance of making informed dietary choices. Oat milk and soy milk have emerged as popular dairy alternatives, each offering unique nutritional benefits. Choosing between them can significantly impact your health and daily nutrition.

Oat milk is celebrated for its creamy texture and sweet flavor, making it a favorite in coffees and smoothies. It’s a great source of fiber, which can aid in digestion and promote heart health. On the other hand, soy milk stands out for its high protein content, comparable to cow’s milk, supporting muscle repair and growth.

Incorporating the right plant-based milk into your diet depends on your nutritional needs and taste preferences. Deciding between oat milk vs soy milk can be a confusing choice, but I’ll make it easier here!

two cups of milk on a table with oat milk vs soy milk written on it.

Nutritional Comparison

When deciding between oat milk and soy milk, understanding their nutritional profiles is key. 

Oat milk is generally lower in protein but high in carbohydrates and dietary fibers, making it an excellent energy source and beneficial for digestive health. It’s particularly suitable for those looking to increase their fiber intake and maybe needing a pre-workout drink.

Soy milk, in contrast, has a much higher nutritional value.  With a higher protein content, essential for muscle maintenance and overall health. It also contains vital nutrients like iron and potassium, which are crucial for blood health and regulating blood pressure. 

Soy milk’s balanced composition of fats, proteins, and carbohydrates makes it a closer match to cow’s milk in terms of nutritional value.

Choosing between oat and soy milk should be based on your dietary goals. If you’re seeking to boost your protein intake, especially in a plant-based diet, soy milk is an excellent choice. 

For those focusing on heart health or needing a gentle, fiber-rich milk alternative, oat milk may be the way to go.

oat milk vs soy milk nutritional comparison in a table.

Oat Milk Nutrition

  • Name: Oat Milk
  • Serving Size: 1 cup (240 mL)
  • Calories: Approximately 120 kcal
  • Fat: Around 5 g
  • Protein: About 3 g
  • Carbohydrates: Approximately 16 g
  • Sugar: Varies (often around 7 g in unsweetened varieties)
  • Vitamins and Minerals:
    • Often fortified with Calcium
    • Often fortified with Vitamin D
    • May contain Vitamin B12 (in fortified versions)
    • May contain Iron (in fortified versions)

Soy Milk Nutrition

Soy Milk Nutrition (Per 1 Cup Serving – 240 mL)

  • Name: Soy Milk
  • Serving Size: 1 cup (240 mL)
  • Calories: Approximately 80-90 kcal
  • Fat: Around 4 g
  • Protein: About 7-9 g
  • Carbohydrates: Approximately 4 g
  • Sugar: Minimal (less than 1 g in unsweetened varieties)
  • Vitamins and Minerals:
    • Often fortified with Calcium
    • Often fortified with Vitamin D
    • May contain Vitamin B12 (in fortified versions)
    • Good source of Potassium
    • Contains Iron

Health Benefits

Both oat milk and soy milk offer health benefits, making them excellent additions to a balanced diet. Oat milk’s high fiber content supports heart health by helping to lower cholesterol levels. 

This makes it a smart choice for those looking to improve their cardiovascular health or manage existing heart conditions.

Soy milk, rich in high-quality plant-based protein, not only aids in muscle repair and growth but also contributes to a feeling of fullness, which can be beneficial for weight management. Its content of iron and potassium plays a crucial role in maintaining healthy blood pressure and preventing anemia, especially important for vegetarians and vegans who might not get enough of these nutrients from other sources.

Incorporating these plant-based milks into your diet can contribute to overall well-being. Whether you choose oat milk for its heart-healthy benefits or soy milk for its protein and mineral content, both options can help you meet your nutritional needs in a delicious and versatile way.

Health Benefits for Seniors

For seniors, choosing between oat milk and soy milk involves considering nutritional needs that change with age. Soy milk stands out for its high protein content, essential for maintaining muscle mass, which tends to decrease in older adults. 

Its rich array of vitamins and minerals, including calcium when fortified, supports bone health, making it a valuable choice for preventing osteoporosis.

Oat milk, with its higher fiber content, can aid in digestive health, an important aspect for seniors who may face digestive issues. The cardiovascular benefits of oat milk, such as lowering bad cholesterol levels, align well with the common health concerns in older age.

Both oat and soy milk can be healthful additions to a senior’s diet, provided they choose unsweetened varieties to avoid excess sugar intake. 

As with any dietary change, it’s beneficial for seniors to consult with a healthcare provider to ensure these milk alternatives complement their overall nutritional needs and health conditions.

Comparing Them to Cow’s Milk

When comparing oat milk, soy milk, and cow’s milk nutritionally, there are several key differences to highlight. Cow’s milk is naturally rich in protein, calcium, and vitamins B12 and D, offering about 8 grams of protein and 149 calories per 8-ounce serving. It also contains saturated fats, with about 8 grams per serving, contributing to its creamy texture.

On the other hand, soy milk stands out as a plant-based alternative closest to cow’s milk in terms of protein content, providing about 7 grams of protein and 80 to 100 calories per serving. It’s also a good source of potassium, vitamins A and D, and is often fortified with calcium.

Oat milk, while lower in protein at about 2 to 4 grams per serving, offers a higher carbohydrate content, contributing to its naturally sweet flavor. It typically contains about 100 to 120 calories per serving and is enriched with vitamins and minerals, including calcium and vitamin D.

Both soy and oat milks are cholesterol-free and low in saturated fats, making them heart-healthy alternatives to cow’s milk.

oat milk vs soy milk comparison chart.

Environmental Impact

The production of oat milk and soy milk carries a relatively low environmental impact.  Oat milk production is particularly noted for its efficient water usage and lower greenhouse gas emissions. 

It’s an eco-friendly option that requires less water and land than many other plant-based milks.

Soy milk also presents a sustainable alternative, though its environmental benefits can vary depending on the region of cultivation and farming practices. Responsible sourcing and choosing soy products from areas that avoid deforestation can mitigate some of the environmental concerns associated with soy production.

You can pick whichever one you want, though I wouldn’t let environmental impact dictate my choice.  Dairy milk farmers try their best as well to be respectful of the environment, so nutrition should be a bigger choice.

Taste and Culinary Uses

The choice between oat milk and soy milk often comes down to personal taste preferences and culinary applications. 

Oat milk is known for its naturally sweet flavor and creamy texture, making it a popular choice for coffee, smoothies, and baking. Its creaminess enhances the body of beverages and can add a subtle sweetness to recipes without the need for added sugars.

Soy milk, with its neutral to slightly beany flavor, is versatile in both sweet and savory dishes. It’s particularly well-suited for cooking, as its high protein content provides a texture similar to cow’s milk when heated.  Making it ideal for sauces and soups. 

Soy milk’s ability to create a stable foam makes it a favorite for baristas crafting lattes and cappuccinos.

Whether you prefer the sweetness of oat milk for your morning cereal or the culinary versatility of soy milk, both can be delicious and nutritious plant-based additions to your diet. Experimenting with these milks in various recipes can help you discover new flavors and textures that complement your meals.

Potential Downsides

While oat milk and soy milk are healthy choices for many, it’s important to be aware of their potential downsides. 

One concern with some commercial oat milk products is their added sugar content. Choosing unsweetened varieties can help avoid unnecessary sugar intake. Also at milk’s higher carbohydrate content might not suit those on low-carb or ketogenic diets.

Soy milk, on the other hand, has been subject to scrutiny over its phytoestrogen content, compounds that mimic estrogen in the body. 

However, most research indicates that moderate consumption of soy products, including soy milk, is safe and may even offer health benefits. Still, individuals with thyroid issues or hormonal sensitivities should consult with a healthcare provider.

Both oat and soy milks can contain additives and preservatives to extend shelf life and improve taste. Reading labels and choosing products with minimal ingredients can ensure you’re getting the healthiest version of these plant-based milks.

Consumer Preferences

The popularity of oat milk and soy milk reflects a growing consumer preference for plant-based alternatives to dairy. 

Oat milk has surged in popularity due to its creamy texture and environmentally friendly production process, appealing to those looking for sustainable and delicious dairy substitutes. Its natural sweetness and ability to froth well make it a favorite in coffee shops and among home baristas.

Soy milk, with its long-standing presence in the market, is valued for its nutritional profile, closely mirroring that of cow’s milk in terms of protein and offering a range of fortified options. It remains a staple for those prioritizing high protein content and a more neutral flavor in their cooking and baking endeavors.

Ultimately, the choice between oat milk and soy milk often comes down to personal preference and dietary needs. As the demand for plant-based options continues to grow, these milks stand out for their versatility, health benefits, catering to a wide range of tastes and preferences.


Deciding between oat milk and soy milk should be guided by your personal health objectives and dietary tastes. Oat milk, with its creamy texture and natural sweetness, is perfect for those seeking to enhance their fiber intake for better digestive health or who enjoy a sweeter taste in their beverages and meals. 

On the other hand, soy milk offers a robust option rich in protein and essential nutrients, making it ideal for individuals following vegan diets or those focusing on muscle maintenance and overall well-being.

Each choice supports a range of health benefits, from heart health with oat milk’s fiber content to the nutritional completeness of soy milk, mirroring the protein level of cow’s milk. The decision is not just about nutrition; it’s also about what fits best into your lifestyle and meets your taste preferences.

As you explore the world of plant-based milks, remember that the ultimate choice between oat and soy milk depends on what works best for you. Whether you’re drawn to the sweetness of oat milk or the nutritional profile of soy milk, incorporating these plant-based options into your diet can be a delicious and healthful decision.


Is Oat Milk or Soy Milk Better for Weight Loss?

For weight loss, soy milk might be a better choice due to its lower calorie content and higher protein levels, which can aid in satiety and muscle maintenance. However, individual responses can vary, and it’s important to consider overall dietary habits and preferences.

Can People with Lactose Intolerance Consume Oat and Soy Milk?

Yes, both oat milk and soy milk are lactose-free, making them suitable alternatives for individuals with lactose intolerance. They provide similar textures and flavors to dairy milk without causing the discomfort associated with lactose digestion issues.

How Do Oat Milk and Soy Milk Impact Blood Sugar Levels?

Oat milk, with its higher carbohydrate content, may have a more significant impact on blood sugar levels, especially if sweetened. Soy milk, with lower carbs and sugars, might be a better option for those managing blood sugar levels, such as individuals with diabetes.

Michelle saari dietitian
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Michelle Saari is a Registered Dietitian based in Canada. She has a Master's Degree in Human Nutritional Sciences and is a passionate advocate for spreading easy to understand, reliable, and trustworthy nutrition information. She is currently a full time online entrepreneur with two nutrition focused websites.

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