Nutrition 7 MIN READ

The Impact of Dairy Food On Insulin And Blood Sugar Levels

The milk from a lactating animal and the products made from it are labelled dairy – like butter, cheese, and yogurt. Nutritionally, dairy contains carbohydrates, fats, protein, and naturally occurring sugar.

Written by Team Ultrahuman

Oct 09, 2021
Insulin BloodSugar Levels

What is Dairy Food?

The milk from a lactating animal and the products made from it are labelled dairy – like butter, cheese, and yogurt. Nutritionally, dairy contains carbohydrates, fats, protein, and naturally occurring sugar. It is usually available in versions that alter the proportions of these energy sources.

The main carbohydrate in dairy is lactose, a milk sugar that the body breaks down with a digestive enzyme called lactase. The research on it gives dissimilar results, further fueling the dinner table debates about its consumption. 

As dairy carries both fats and protein, it can steadily release energy into one’s bloodstream. This moderated pace gives dairy a low glycemic index, a metric that indicates how quickly the body processes carbohydrates into glucose.

Foods with low glycemic indexes are considered good, in that they affect blood sugar moderately instead of causing volatile spikes in the level.

It is possible for two foods with similar counts of carbohydrates to have differing glycemic numbers, the lower being indicative of a slower release of energy.

One can measure the glycemic index number using this guide

  1. 55 or less (good, low)
  2. 56-69 (medium) 
  3. 70 or more (high, bad). 

The Effect of Dairy Food (Milk & Lactose) on Insulin

It’s important to understand how insulin works in order to comprehend its connection with dairy. Insulin is a hormone created by the pancreas that controls the amount of glucose in a person’s bloodstream at any given moment. It helps store glucose in the liver, fat, and muscles, and regulates the body’s metabolism of carbohydrates, fats, and proteins.

After eating, blood sugar levels rise. Insulin released by the pancreas helps the cells to absorb blood sugar for energy and storage. With this absorption, glucose levels in the bloodstream begin to decline. The pancreas then produces glucagon, a hormone that prompts the liver to release stored sugar.

This interaction of glucagon and blood sugar ensures stable blood glucose levels in the body and the brain. The cells of individuals who have insulin resistance don’t respond well to insulin, barring glucose from entering them with ease.

The glucose level in their blood rises over time even as their body produces more insulin as the cells resolutely resist insulin. 

Lactose Metabolism

Lactose is speedily metabolized into simpler sugars and absorbed in your intestines if you produce sufficient enzymes. If not, lactose intolerance manifests and leads to various gastrointestinal symptoms.

Lactose is a type of carbohydrate known as a disaccharide. It is a molecule composed of two simple sugars – galactose and glucose. All female mammals, including women, produce milk that contains lactose. The percentage of lactose in milk can range between 2 percent and 8 percent.

The body begins to metabolize lactose in the intestines with the help of lactase, an enzyme lining the small intestine. The enzyme attaches to lactose and divides it into molecules of galactose and glucose.

Glucose is immediately absorbed into the bloodstream and used by cells to generate energy. Galactose cannot be utilised by the body firsthand, so it is modified into glucose after further activity by lactase and other enzymes.

Impairment of lactose metabolism occurs when insufficient enzymes are produced.

A lack of lactase makes way for a condition called lactose intolerance, which is marked by bloating, flatulence and diarrhea.

Undigested lactose wanders to the large intestine and offers a food source to the ‘good bacteria’. The bacteria is conducive to fermentation of the sucrose in order to metabolise it, which produces gas and other symptoms.

Further, the inability to transform galactose into glucose causes galactosemia. When too much galactose piles up in the blood due to a dearth of some enzymes like galactose kinase, it can be detrimental to the brain and other organs.

Furthermore, dairy is an insulin secretagogue (a substance that causes another substance to be secreted). Dairy and its products catalyze the secretion of insulin from the pancreas. This can happen beyond the expected range for a food with a low glycemic index count. Surplus insulin can debilitate the glucose rise but makes one more insulin resistant the following day.

Frequent consumption of dairy causes disproportionate insulin spikes when considered from the perspective of carbohydrate content, up to as high as 3-6 times. It is believed the protein in milk causes this spike, as certain studies of whey protein consumption have detected spikes of as high as 90% in insulin count after a meal.

Amino acids released after eating are also shown to prompt insulin release. Food proteins vary in their capacity to stimulate insulin secretion, conceivably by differently impacting the early release of incretin hormones (gut peptides that are secreted after nutrient intake and inciting insulin secretion in combination with hyperglycemia).

Milk proteins bear insulinotropic (stimulating or affecting the production and activity of insulin) properties.

glucose blood sugar

How does dairy food affect glucose & blood sugar levels?

As dairy consumption may cause insulin spikes, it can indirectly affect blood sugar levels by increasing the glucose count present in our bodies. However, the scientific findings are both specific, and uncertain.

A 2014 review of 10 studies found that:

  1. For people in a healthy weight range, more dairy consumption does not affect glucose metabolism. For those outside it, the mixed results hinted that dairy effects carry less importance than reducing weight or increasing exercise to prevent or reduce the risk of type 2 diabetes.
  2. This review also shed light on the variance in results. As many factors can have an impact on insulin sensitivity, and they can all affect each other, the change in any factor could affect others. 

How to navigate dairy food in your diet

Since much dairy can lead to a sensitive insulin response, the particulars of it vary based on the fat and protein present in the food.

However, we can use these recommendations from research and studies as a base for deciding on dairy:

  1. In moderate amounts, milk could reduce the risk of ‘central obesity’ in males. It can also reduce the risk of diabetes. Since there is a study that ties saturated fats and insulin resistance together, it is prudent to have one’s milk in moderation.
  2. Fermented dairy, or products such as kefir, yogurt, and cheese are best unsweetened. A study in Sweden discovered that adding yogurt and a pickle of vinegar-preserved cucumber to a breakfast of high-carb white bread reduced blood sugar and insulin levels.
  3. Ice cream is high-fat and carries a lot of sugar. A study puts it at the same level of nutrition as a candy bar.
  4. Harvard researchers reported in BMC Medicine that consuming a serving a day of yogurt lowered diabetes risk by about 19%. While the cause of this correlation is still not comprehensively ascertained, experts believe that the fatty acids and probiotics in yogurt may improve the body’s usage of insulin. 
  5. A study suggests that both high- and low-fat variants of cheese enhance insulin sensitivity (how well cells respond to insulin).

How should one explore replacing dairy?

Due to lactose intolerance, ethical reasons, or sometimes even to experiment, dairy could be replaced in one’s diet. Tofu instead of cottage cheese, almond or peanut butter instead of regular butter, and coconut, oat, and almond milk are familiar phrases in urban vocabularies around the world.

The advice around picking such substitutes is:

  1. Seek out unsweetened servings of nut and bean milks. They may have less protein than regular milk, yet they skip the insulinogenic effects as they carry bare amounts of sugar. 
  2. While there may not be added sugar to such milks, the steps of manufacturing or processing them can alter their nutritional composition, thereby making them have more sugar than their base or when compared to regular milk.


Dairy is a repository of carbohydrates, fats, protein, and naturally occurring sugar. The main carbohydrate in dairy is lactose. An impairment of lactose metabolism causes lactose intolerance. Dairy is an insulin secretagogue (a substance that promotes secretion). There is a lack of clear consensus about the notion of dairy’s insulinogenic effect as beneficial or detrimental to our metabolic health. Although most dairy products prompt an enhanced insulin response, the effect on insulin sensitivity and glucose levels is known to change according to the food’s protein and fat composition.  Experts believe that the fatty acids and probiotics in yogurt may improve the body’s usage of insulin in some individuals, making it the likely star of dairy products. 

Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns and before undertaking a new health care regimen including making any dietary or lifestyle changes.


  1. The serum insulin and plasma glucose responses to milk and fruit products in Type 2 (non-insulin-dependent) diabetic patients | SpringerLink
  2. Inconsistency between glycemic and insulinemic responses to regular and fermented milk products | The American Journal of Clinical Nutrition | Oxford Academic (
  3. Glycemia and insulinemia in healthy subjects after lactose-equivalent meals of milk and other food proteins: the role of plasma amino acids and incretins | The American Journal of Clinical Nutrition | Oxford Academic (
  4. Dairy consumption and insulin sensitivity: a systematic review of short- and long-term intervention studies – PubMed (
  5. High dairy fat intake related to less central obesity: A male cohort study with 12 years’ follow-up (

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