Protein plays an essential role in the recovery and development of muscle mass in athletes. To reach their goals and cover higher requirements, many athletes resort to dietary supplements such as the famous whey protein. However, some of them experience digestive problems such as bloating, flatulence or, more rarely, constipation after consuming these protein powders.
In many cases, these inconveniences are linked to lactose intolerance. As whey is derived from milk, it may contain traces of this sugar, even though filtration processes can greatly reduce its content, particularly in the case of whey isolate.
So, does whey protein really constipate? What are the reasons for these digestive problems, and how can they be remedied? This article provides a comprehensive overview of the subject of protein and intestinal transit.
Contents
What are the different types of protein powder and their characteristics?
Whey proteins
Whey protein is derived from whey. They are of animal origin and have a high biological value, i.e.they contain all the essential amino acids in optimal quantities for the human body (notably the BCAAs). There are several types of whey, depending on their degree of purification:
- Concentrated whey With a protein content generally under 80%, it also contains a little lactose, lipids and minerals.
- Whey isolate: purer, it contains over 85% protein and very little lactose and fat. It is often better tolerated by the digestive system.
- Hydrolyzed whey: this is a "pre-digested" form of whey in which the proteins are broken down into small peptides, facilitating their absorption by the small intestine. However, it is often much more expensive, requires the action of solvents for hydrolysis, and no studies have demonstrated superior efficacy.
Overall, whey isolate appears to be the best compromise in terms of quality, digestibility and price. Whey proteins are rapidly assimilated by the body and effectively stimulate muscle protein synthesis(1).
Plant proteins
For vegans or people with lactose intolerance, there are also plant-based proteins. These will have a lower profile in essential amino acids and BCAAs. The best-known are :
- Soy proteins: with around 90% protein, they have a good amino acid profile but are a little less well assimilated.
- Pea protein: highly digestible, rich in fiber and minerals.
- Rice proteins: with a protein content of around 80%, they are hypoallergenic and contain little fat.
- Hemp proteins: less concentrated (50%), they provide fiber and omega-3.
Although interesting, vegetable proteins often have a less complete amino acid profile. It is advisable to combine them (e.g. rice and peas) to obtain a slightly more complete intake. They are well suited to a varied diet , but are acknowledged to be less effective than whey for building muscle mass.
In conclusion, the choice of protein powder depends on your objectives, your eating habits and your digestive tolerance. Here's a table summarizing the main characteristics of different proteins:
| Type | Protein content | Digestion | Benefits | Disadvantages |
|---|---|---|---|---|
| Whey concentrate | ~80% | Fast | Price | Lactose, lipids |
| Whey isolate | >90% | Very fast | Pure, low-lactose | A little more expensive |
| Hydrolyzed Whey | >90% | Very fast | Pre-digested | Expensive, not more efficient |
| Casein | ~80% | Slow | Anti-catabolic | Less rich in BCAAs |
| Soybeans | Variable | Intermediate | Plant-based, good content | Less well assimilated |
| Peas | Variable | Fast | Easily digestible, rich in fibre | Incomplete profile |
| Rice | Variable | Fast | Hypoallergenic | Incomplete profile |
| Hemp | Variable | Intermediate | Omega-3, fiber | Low content |
Whatever protein you choose, it's important to pay attention to product quality and composition (without additives), to vary sources and tointegrate itinto a balanced diet and healthy lifestyle with regular physical activity, to derive the full benefits without risk to health.
Can certain proteins, such as whey, disrupt transit?
Some people report digestive problems - hypothetically linked to whey - such as bloating, cramps, flatulence or constipation after consuming shakers.
In reality, these disorders are generally not directly linked to the protein itself, but rather to lactose intolerance. As whey is derived from milk, it may contain traces of lactose, even though filtration processes can greatly reduce its content. People with lactose intolerance don't produce enough lactase, the enzyme needed to digest lactose. Lactose then reaches the intestine, where it is fermented by bacteria, causing gas, bloating and sometimes constipation.
According to studies(2), up to 68% of the world's population is lactose intolerant to varying degrees. However, you need to be careful with this figure, as it varies greatly by region: for example, it's much lower in Europe than in the USA. If you already have problems digesting milk and dairy products, there's a good chance that whey will cause you discomfort, depending on its type. It is therefore very important to choose isolate-based products (check the ingredients list).
If you are not intolerant or allergic to dairy proteins, whey is absolutely safe for your health.
Another factor that can disrupt transit is the presence of additives in some whey powders: sweeteners, thickeners, emulsifiers... These ingredients can irritate the stomach and intestine, altering the intestinal microbiota and causing symptoms such as irritable bowel syndrome or, on the contrary, constipation. It is therefore preferable to choose high-quality, additive-free whey proteins.
A few tips to limit digestive problems with whey:
- Do not exceed 1 to 2 shakers per day, i.e. 25 to 50g of protein. Whey is a dietary supplement and should not replace balanced meals.
- Keep well hydrated to facilitate the whey's passage through the digestive system. Mix the powder with sufficient water or milk.
- Choose high-quality whey that is low in lactose (isolates) and additive-free. Choose European brands that are transparent about their production processes.
- In the case of proven intolerance, opt for vegetable proteins (peas, rice, hemp...), which are generally better tolerated.
Whey remains an excellent source of amino acids for athletes. But it's not essential. The most important thing is to have an adequate protein intake, whether through food or supplements. In the event of persistent digestive problems, don't hesitate to adapt your intake or test other options. The most important thing is to respect your body and your well-being.
Here's a small table to summarize the main ideas of the article:
| 🏋️ Protein | Muscles and recovery |
|---|---|
| 🌾 Whey | A safe and studied complement |
| 🥛 Lactose | Presence, attention intolerance, little or not in isolates |
| 🔬 Filtration | Reduces lactose |
| 🧪 Types of whey | Concentrated, isolate, hydrolyzed |
| 🥤 Whey isolate | Best compromise |
| 🌱 Vegetable proteins | Less complete alternatives for vegans |
| 🚫 Additives | Possible digestive problems |
| 💧 Hydration | Facilitates digestion |
| 🥄 Quantity | 1-2 shakers a day |
