Protein Powder & Fruit in a Blender - Ask a Nutritionist

July 6, 2023

What are branch chain amino acids and do only serious athlete need them? Does adding fruit to your protein smoothie change how your intestines absorb nutrients? Tune into this week's episode of Ask a Nutritionist with Teresa to find out all these answers and more.

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Welcome to the “Ask a Nutritionist” podcast, brought to you by Nutritional Weight and Wellness. We are thrilled to have you join us today as we discuss the connection between what you eat and how you feel, and share practical real life solutions for healthier living through balanced nutrition. Now let's get started.

TERESA: Welcome to Dishing Up Nutrition's midweek segment called “Ask a Nutritionist”. I'm Teresa Wagner, I'm a Registered and Licensed Dietitian. And on today's show, brought to you by Nutritional Weight and Wellness, I will be answering a nutrition question we've received from one of our Dishing Up Nutrition listeners. Today's question is, “I recently read a book that said protein powder contains branch chain amino acids, and those are not good for typical people unless they are a serious athlete.” She's wondering what we think about this: She also read in the book that putting fruit in a blender is not good for the lining of the intestines because it's not in its original form, and that is needed in order for the fiber to line the intestines properly.

Branch chain amino acids are required for health

I'm going to start the podcast with answering your question right away and then give the explanation following that brief answer. So first off, no, I do not agree with either of the statements in the book that you read. Branch chain amino acids are required for the health of all people, and in standard protein powders, there isn't excessive amounts of protein or excessive amounts of these branch chain amino acids. Protein powders are actually quite good and healthy for most people to include in a part of their daily diet.

Blending fruit is NOT bad for the lining of the intestines

For the second part of the question, no putting fruit in a blender is not bad for the lining of the intestines and the ability for fiber to function properly. So that's my brief answer.

What are amino acids?

Let's dig a little deeper and we'll start with the amino acids. So first off, what are amino acids? Well, amino acids are the building blocks of protein. Proteins are just long chains of amino acids. Your body has thousands of different proteins that each have important jobs within the body. Each protein has its own sequence of amino acids. This sequence makes the protein take different shapes and have different functions in your body.

I like the way an article from the Cleveland Clinic explains it. You can think of amino acids like the letters in the alphabet. When you combine the letters in various ways, you make different words. The same goes for amino acids. When you combine them in various ways, you make different proteins.

Essential amino acids are needed in the body

Your body needs 20 different kinds of amino acids to work as it should. And as I said earlier, these 20 amino acids combine in different ways to make different proteins in the body, but you can't make nine of those amino acids on your own. These amino acids are called essential amino acids. You must get them from the food that you eat. And I know that just recently Brandy did a segment on animal proteins and she also talks about the essential amino acids. So if you want a different spin on the protein topic, tune into Brandy's podcast on amino acids.

So these essential amino acids, you must get them from the food that you eat. And I'm actually going to name the nine essential amino acids. There will not be a quiz later, but we will be talking about a couple of them coming up. So I just want you to have an idea of what the names are. So the nine essential amino acids are histidine, isoleucine, lysine, leucine, methionine, phenylalanine, threonine, tryptophan, and valine. The other 11 amino acids: I will spare you their names. Those are the non-essential amino acids.

What is the function of amino acids?

Amino acids. So what do they do? Different types of amino acids and the way they're put to together determine the function of each protein, and they're involved in many important roles in the body, including making your digestive enzymes so that it helps you break down the food that you're eating. They help to grow and repair body tissues. They make hormones like insulin, human growth hormone, and your thyroid hormones.

Proteins are the building blocks of your neurotransmitters or your brain chemicals such as dopamine and serotonin. Protein is also, it's a food. So it functions as an energy source for the body and fuel for our, for our body. Protein is responsible for the growth and maintenance of your hair, skin, and nails. It helps to build muscle and bones and it boosts the immune system by activating the defense mechanisms that that immune system has.

Essential amino acids need to come from food (best source is animal protein)

The essential amino acids are the amino acids that our body can't make on its own. And so we need to get this from the foods that we eat. The best sources of those amino acids are found in animal proteins. Amino acids from animal proteins are the most easily absorbed and used by your body of the proteins in our food supply.

What are complete proteins?

The foods that contain all nine essential amino acids are called complete proteins. These foods that contain complete proteins include all the animal proteins, so beef, poultry, fish, eggs, dairy products. But there are some plant-based sources that are complete proteins and that would include some foods like soy, quinoa, buckwheat. They do have all nine essential amino acids as well.

What are incomplete proteins?

Foods that contain some, but not all of the essential amino acids are called incomplete proteins. These foods include nuts, seeds, beans, and most grains. So if you follow a vegetarian or vegan diet, you need to include several different types of these incomplete proteins to ensure that you're making complete proteins or that your body is getting all nine of those essential amino acids.

Okay, so back to the question. The book the listener read said that protein powder containing branch chain amino acids are not good for people unless they're more of a serious athlete. So let's break it down once again. Branch chain amino acids are a part of the group of essential amino acids. Remember that the essential amino acids are necessary for the health of the body, and we have to get them from our diet. And there are three branch chain amino acids. There's leucine, isoleucine, and valine. The branch chain just refers to the chemical structure of these amino acids. The structure has branches.

Branch chain amino acids stimulate the building of muscle

So what's so special about the branch chain amino acids? Well remember that all the proteins have different jobs based on their sequencing. Branch chain amino acids stimulate the building of muscle. That's why they're so popular among people who exercise, particularly the people who lift weights and are looking to gain muscle mass. They're commonly used to improve athletic performance, prevent muscle fatigue and reduce muscle breakdown. And while branch chain amino acids are popular amongst exercise enthusiasts, the protein powder usually provides all nine of the essential amino acids including those branch chain amino acids.

And depending on the source of that protein, the amount of those branch chain amino acids will vary. For example, collagen has a complete amino acid profile having all nine essential amino acids, but it's a pretty poor source of the branch chain amino acids. Whereas whey is an excellent source of the branch chain amino acids. This is the part of the reason why people who exercise also tend to be people who may include protein powders as a part of their diet. It's an easy way to get extra protein in and those muscle building branch chain amino acids as long as you're using the right protein powder.

As far as the question is concerned in regard to what we offer at Nutritional Weight and Wellness, in our Nutrikey whey protein powder, there is about two grams of leucine and a little over one gram of each isoleucine and valine. And considering we recommend eating 100 grams or more of protein per day, those four grams of branch chain amino acids are just a drop in the bucket in our overall protein needs.

The egg white protein powder has a little higher branch chain amino acid content with around five and a half grams of total branch chain amino acid. But the Paleo beef protein powder has a profile similar to the collagen, which is much lower in those branch chain amino acids. So no, using standard protein powders is not going to be overdoing it on the branch chain amino acids even for those who aren't high level athletes. Protein powders made with quality ingredients can be a great addition to anyone's diet.

Which amino acids are most important for muscle synthesis?

And for those who are interested, of the three: leucine, isoleucine and valine, the most important for muscle synthesis and growth is leucine. To stimulate muscle synthesis, we need to eat at least two and a half to three grams of leucine before that will happen. And the earlier we reach that two and a half to three grams in the day, the better for muscle growth and the preservation of the muscle that we have. If we hit this amount of leucine at each of our meals, we'll be in a great place for muscle growth and maintenance.

Keep in mind that diet is just one aspect of muscle growth. In order to grow and maintain our muscles, we do need to work them. But that's a topic for a different podcast. To get that three grams of leucine in whey protein powder, you need about 30 grams of protein, which is about one and a half scoops of that protein powder.

To get it from a food source, we're looking at four ounces of chicken breast, four and a half to five ounces of beef or pork or five eggs. And certainly if you like to have eggs in the morning, five eggs might be a little excessive or a little bit too much volume for you. So one thing that you can do is do two whole eggs and three quarters of a cup of egg whites, and that will get you to that three grams of leucine.

So as you can see, it takes a fair amount of protein to hit the threshold for muscle growth. My guess, for the majority of the people listening, looking up and calculating the amount of leucine you are eating is just getting way too far in the weeds of nutrition science. So my recommendation for you is to just continue to follow what we at Nutritional Weight and Wellness have been saying for years. Eat about four ounces of a variety of different animal proteins at each of your meals and a couple of ounces of protein at snacks, and you'll be hitting all the amino acids, all the essential amino acids, and all the branch chain amino acids your body needs. So I hope that simplifies that for you.

Now, onto the second part of the question asking about putting fruit in a blender and it not being good for the lining of the intestines because it's not in its original form. And according to the book that was read, in order for that fiber to line the intestines properly.

Breaking down the digestive process

So let's start this part off by thinking about what happens in digestion. First, we chew the food, hopefully breaking down that food into small pieces. While in the mouth, those carbohydrates in that fruit will start being broken down by a digestive enzyme called amylase. Then we swallow the food. In the stomach, that food is exposed to stomach acid or hydrochloric acid, and the mechanical churning of the stomach. At this point in the stomach, the food should be almost a smoothie like consistency anyway.

From the stomach to the intestines, the food is exposed to more digestive enzymes, further breaking the food down so that the nutrients can be absorbed. And most nutrient absorption happens in the intestines, particularly the small intestine. So in other words, our digestive process is much harsher than a blender. Going further, generally when someone is saying that blending fruits and vegetables destroys the nutrients, they're usually what they're talking about is blending causes oxidation of those fruits and vegetables, so exposing more of the fruit surface to air, which can cause nutrient loss.

You can think about that like when you cut a banana and you expose it to air, how it browns, that's oxidation. And while there might be some nutrient loss, so this might be a true statement, there might be some nutrient loss, that loss, it's really not that significant.

First of all, not all nutrients are antioxidants. So nutrient loss through oxidation is a non-issue for nutrients that aren't antioxidants like the B vitamins and fiber. And for the nutrients that are antioxidants like vitamin C and vitamin E, copper, selenium, zinc, nutrient loss through oxidation, well, it takes time. So when we blend our protein shakes and then drink them, there isn't much time for that loss to happen.

Fiber remains unchanged even when blended or in the digestive tract

As far as the fiber is concerned, fiber is a type of carbohydrate, but unlike other carbohydrates that are broken down into their digestible sugars, fiber remains intact, not able to be digested. Because of this, it passes through the intestinal tract virtually unchanged, which means that it stands up to the grinding of your teeth and molars to your saliva, to the digestive enzymes, the stomach acid, and it remains unchanged through all of this.

So fiber can withstand all of that. Certainly blending it in your blender is not going to destroy it either. But I do like to back up my statements with some research. So here you go. In the Journal of Nutrition and Food Sciences from 2017, an article titled “Fibrous Cellular Structures are Found in a Commercial Fruit Smoothie and Remain Intact During Simulated Digestion”. So keep in mind that this is a commercially made smoothie, so it's likely that the blender that they're using is much more powerful than our home blenders. In this study, it was shown that a commercial sample of the smoothie has a high concentration of intact fruit cells, which then are preserved during digestion.

This indicates that smoothie processing would offer similar benefits to whole food fruit consumption for the people who are eating them; basically saying that the smoothies have similar benefits as eating the fruit whole. And that's what we would say too, as when you're making your protein shakes, when you're throwing your berries or your banana or whatever you're putting in your protein shakes, that really the benefits of that, that those berries would be the same as if you're just eating them or if you're blending them.

There is another study that was published in the International Journal of Food Science and Nutrition in 2019. The title of that study was the “Glycemic Index, the Glycemic Load, and the Dietary Fiber, Dietary Fiber Characteristics of two Commercially Available Fruit Smoothies”. That's a mouthful. The results of this study showed that dietary fiber was still present in those smoothies after processing.

So once again, the fruit is intact enough for it to be just as beneficial as eating the whole fruit and the fiber is still present so that we still have it for all the wonderful digestive processes that it helps with. So I hope that answers your question. Thank you so much for that question, and thank you so much for listening to Dishing Up Nutrition's “Ask a Nutritionist”. If you have a nutrition question that you'd like us to answer, we invite you to join our Dishing Up Nutrition Facebook community by searching Dishing Up Nutrition on Facebook.

Join Our Dishing Up Nutrition Facebook Group

This private group is moderated by Nutritional Weight and Wellness nutritionists and nutrition educators, and provides our Dishing Up Nutrition listeners with a safe, supportive community to ask questions, share ideas, and get inspired.

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