Mainstream Keto Weight Loss Diet

bacon

In the midst of the Macro Wars came the birth of the newest weight loss fad: The Keto Diet. For the mainstream population, this seemed to be the next logical step of low carb-ism; a more extreme Atkins Diet. Now that fats are healthy again and carbs will make you spiral into a premature death, going Keto is the only way. For the mainstream, going keto entails consuming excessive amounts of processed low quality animal products, keto bombs, nuts, cheese, diet sodas and cutting out all carbohydrates including all grains, most produce, sugar and legumes. In sum, a dietitian’s nightmare. Eventually these individuals set up an appointment with me for weight loss counseling and tell me that “keto” didn’t work for them when they didn’t even do it correctly. It’s been a common theme for a while.

I’m pretty sure when Dr. Wilder coined the term Ketogenic Diet as a therapeutic intervention for epilepsy, he never would have thought it would turn into yet another mainstream weight loss trend that people are incorrectly using by eating a diet full of bacon and cheese in hopes to shed a few.

However, a properly implemented Ketogenic diet has amazing therapeutic potential and I have guided many patients through it for many disease states due to its ability to act on multiple pathways. Basically, when there’s not enough glucose available when you’ve been fasting or restricting carbohydrates, your body will start breaking down stored fat into molecules called ketone bodies, a process called ketosis. Most of your cells can use ketone bodies as a fuel source and serves many other functions. Ketosis works for epilepsy as it reduces the GABA to Glutamate conversion and alters the gut microbiome. Acknowledging the diet’s ability to produce ketones that cross the blood brain barrier to provide an alternative fuel source, the ketogenic diet is being used for diseases that lead to inadequate access to glucose in the brain including GLUT1 Deficiency Syndrome and Alzheimer’s Disease (see also: link) . In some cancers, cancer cells have dysfunctional mitochondria and are unable to use ketones as fuels, so a ketogenic diet (in combination with chemo-radiation) could represent a potential dietary manipulation that creates metabolic oxidative stress in cancer cells and nourishes normal cells (review on ketogenic diet for cancer. Fasting Mimicking Diet seems to be a better approach for cancer).

ketone benefits

Health Benefits of Being in Ketosis

Also, ketones act as signaling metabolites that have beneficial effects on the brain, upregulates genes to generate antioxidants, normalizes blood glucose, reduces chronic inflammation and reactive oxygen species, and lowers insulin, which is useful for cardiovascular disease, Type 2 Diabetes and Alzheimer’s Disease. This is what really got me interested in the diet many years ago.

The Ketogenic Diet helps provide metabolic flexibility, allowing us to be adept at burning stored energy in the form of fat and ketones, instead of being controlled by hunger and requiring a regimented carbohydrate bolus every few hours. I believe inducing this state can be used for patients for metabolic syndrome or longevity – via the ketogenic diet or fasting protocols (like intermittent fasting or time restricted feeding). This can even be useful for long distance sports.

But, the mainstream Keto Diet, will most likely not produce these effects because it is not done correctly. That is the main issue with this diet. It is misunderstood and nobody knows how to do it! There is also a lot of bias against ketogenic diets in the research and clinical field currently, which makes reading research articles rather amusing (and frustrating)!

Another issue is that people are not openly discussing the adverse effects of diet. Because of the macro wars – people tend to pick sides. They are either low carb or low fat. It’s time to be more analytical. The question is not: is this diet good or bad. The question should be how should this diet be implemented, who should not be on this diet and why, what biomarkers should we look out for? Is anything in nutrition science ever that black and white? Why should this be?

 

The Mainstream Keto Movement

The ketogenic diet caught mainstream attention because of recent backlash against conventional diet wisdom that promoted carbohydrate consumption in place of fats and cholesterol. Most have probably read this detailed in articles in the Washington Post and Time Magazine. These articles suggest that the low-fat dietary recommendations are what lead to obesity and diabetes epidemic because refined carbohydrates lead to an insulin response, contributing to hyperinsulinemia, more visceral fat storage and exacerbation of metabolic syndrome (also known as the carbohydrate- insulin model of obesity). This is a hotly debated topic.

Others argued that the average person does not follow dietary guideline recommendations, so the low-fat recommendations on the guidelines would not have affected the public’s health. This is true, the dietary guidelines don’t appear to influence consumer intake of different food groups (i.e. American’s fat intake increased during the 1990s, which was during the “low fat” times). However, the guidelines do influence what food products are out there and what is served in school or public programs. For example, whole milk is not allowed for children whereas low-fat chocolate milk is (I am curious to see when this will change, since there’s no association between diary fats and mortality).

Another theory is that it may not be the macronutrients of food causing the obesity epidemic after all. Low fat or low carb or not, majority of Americans fail to get even close to the recommended 5 servings of fruits and vegetables a day. As Dr. Katz discusses in his article, the low-fat movement led to more low-fat high sugar junk foods and really isn’t fair to say that the macronutrient composition of the diet is what lead to the obesity epidemic. There are many ways to interpret a low-fat recommendation. Which way do you think is more popular? The more convenient one or one that leads to you chopping veggies and cooking fish??

These two are versions of a low fat diet. Look how drastically different they are!

Nutrient dense low fat diet (DASH) Mainstream “low-fat” diet*
1 whole wheat bagel with 2 tbsp peanut butter, 1 orange, 1 cup fat-free milk 1 bowl of cereal with fat-free milk, 1 orange juice, Dannon yogurt, 1 coffee with 3 tsp sugar
Spinach salad with 4 cups spinach, 1 sliced pear, ½ cup mandarin orange, 1/3 cup slivered almonds, 2 tbsp red wine vinaigrette, 12 wheat crackers, 1 cup fat-free milk Ham and low-fat cheese sandwich with white bread, 1 bag of baked lays, Nutrigrain bar, 12 oz coke
4oz baked cod, ½ cup brown rice with veggies, ½ cup green beans, 1 sourdough roll, 2 tsp olive oil, 1 cup fresh berries Grilled chicken sandwich with fries and 12 oz coke
Snack: 1 cup fat-free low calorie yogurt and 4 vanilla wafers Snack: popcorn, low-fat cheese
1920 kcal, 56g fat, 10 g sat fat, 280g carbohydrates (120g sugar), 93 g protein 2030 kcal, 53g fat, 11g sat fat, 317 g carbohydrates (158g sugar), 84g protein
Fiber: 39g

Fat break down: monounsaturated: 27.6 grams, polyunsaturated: 16.8 grams, omega-3: 1.1 grams, omega-6: 10.8 grams, saturated fat: 9.3 grams

 

 

Fiber: 17.9 grams

Fat breakdown: 3.9 grams monounsaturated, 2.3 grams polyunsaturated, 0.1 grams omega-3, 1.6 grams omega-6, 13.1 grams saturated fat

*example 24 hour recall from one of my patients

low fat

From my experience as a dietitian and working with many patients throughout the years, I have to say that it’s not only the overconsumption carbohydrates that contributed to their health problems. Metabolic syndrome and complicated disease states are very unlikely to be caused by just one factor. In many cases, their whole diet was not great and needed work. It was commonly due to a combination of severe lack of produce, poor-quality foods, other lifestyle factors and yes, excess refined carbohydrates. Many of my patients were under chronic stress, had sleep deprivation, were night shift workers, inactive and were eating late at night. Eliminating the sugar and refined carbohydrates would have been a great start for my patients.

However, the low-carb movement did not stop with just eliminating added sugars. It created public confusion, and many began to fear all carbohydrates including most produce, fibrous beans, and high fiber grains. Interestingly, these individuals were still drinking soda but would not touch quinoa, brown rice, berries and carrots! Now these foods are put in the “bad” category, leaving my patients feeling riddled with guilt whenever they eat something that contains carbohydrates.

So, many of my patients thought that they needed to eliminate all carbohydrates and only eat fat like butter and bacon like all of the websites, blogs and magazines claimed. I know the ketogenic diet is far more involved than just adding bacon. But this fact is clearly not known to all. It’s not just a more extreme version of the Atkins Diet (And, funnily enough, the Atkins Diet was not intended to be used in that manner either).

The ketogenic diet is not just about dropping carbohydrates even further than just a low carbohydrate diet (~20-50 grams/day for average person) and eating a lot of fat. Protein may also need to be decreased, calories and the type of fat seems to matter for some patients. This takes quite a bit of knowledge of what carbohydrates, fats and proteins are, how to count and track them. Also, it takes understanding that you will need to measure blood ketones to see if you are in ketosis.

Additionally, because of the dietary restrictions of the ketogenic diet (i.e. cutting out multiple food groups), individuals on this diet need to be very careful to ensure they are getting adequate nutrients through high quality foods, plenty of produce and supplementing carefully with electrolytes (i.e. I have had patients who required up to 5 grams of additional salt per day). Inducing ketosis has great health benefits but still needs to be done carefully in the context of an overall healthy diet. One study compared the micronutrient quality of several weight loss diets including Atkins, Ornish, Zone and LEARN using 24 hour food recalls. It was found that while energy intakes were similar, the Atkins group had the most nutrient deficiencies (thiamine, folate, vitamin C, iron and magnesium) and lowest fiber intake.

Differences between therapeutic ketogenic diet and mainstream keto

Here is an example of a nutrient dense, therapeutic ketogenic diet and what I typically see my patients eating. The Therapetuic Ketogenic Diet is an example from the 14 day low carb primal keto ebook.

nutrient dense vs mainstream

Nutrient Dense Ketogenic Diet Mainstream Keto Diet*
Chocolate Chia Pudding made with chia seeds, coconut milk, raw cacao powder, stevia, cinnamon and dark chocolate, ¼ cup of berries Bulletproof Coffee

2 eggs in 1 tbsp butter, 2 bacon strips, 1 oz cheese

Keto Frittata made with whole omega-3 eggs, asparagus, onions, red bell pepper, goat cheese, pancetta, herbs, EVOO and full fat whipping cream 3 oz Deli meat, 1 oz cheese, low carb bread

Triple zero oikios yogurt,1 oz flavored almonds

Salmon with Creamy Spinach using spinach, coconut milk, ghee (or coconut oil or EVOO), hollandaise sauce Low Carb Protein Shake

3 Keto bomb (made with coconut oil, cocoa powder, peanut butter, stevia), 1 oz peanuts

Beverages: Water, Bone Broth Beverages: Crystal light, diet coke
1680 kcal, 40 g carbs, 69g protein, 136g fat

 

1851 kcal, 43 g carbs, 107 g protein, 147.3g fat

16.7 grams fiber

Breakdown of the fat:

Monounsaturated: 59 grams

Polyunsaturated: 23 grams

omega-3: 12 grams

omega-6: 11 grams

saturated fat: 43.9 grams

 

Breakdown of the fat:

Monounsaturated: 32.3 grams

Polyunsaturated: 11.9 grams

omega-3: 0.3 grams

omega-6: 10.8 grams

Saturated Fat: 70.7 grams

*24 hr recall from one patient

While the carbohydrates are the same in both diets and are >50 grams, which many protocols recommend, these diets are incredibly different. Let’s compare these two diets. Also, this mainstream keto diet is very unlikely to induce ketosis due to the high protein content, artificial sweeteners, and poor diet quality. But, like majority of my patients who have claimed to try this diet, this individual did not measure blood (or urine) ketone level so it is difficult for me to know. If you are seriously giving this diet a try, it is important to check ketone level.

Therapeutic Ketogenic Diet Mainstream Keto
Protein Sources Majority from high quality sources from omega-3 eggs, salmon. Small amount of cheese. Processed sources including artificially sweetened yogurts, deli meats, processed meats, nut butters and cheese
Fat Sources Higher unsaturated fat: saturated fat ratio from grass fed butter, omega-3 eggs, salmon, coconut milk, ghee, olive oil, avocado, goat cheese, chia seeds Majority from saturated fats from processed meats (bacon), coconut oil, cheese.

More emphasis on omega 6: omega 3 ratio (i.e. more nuts)

Produce Plenty of vegetables, small amount of berries Minimal or none
Artificial Sweeteners Small amount Plenty in crystal light, yogurts, diet products
Micronutrient Analysis

keto micro

People are ignoring the “overall healthy diet part” and are completely missing the point. It seems that people are solely focused on eliminating carbohydrates and instead, consuming tasty fats and forgetting about nutrient dense foods including produce and high-quality meat sources. Remember that you still need to eat a healthy diet.

The nutrient dense version of the ketogenic diet contains plenty of phytonutrients, micronutrients, fiber, a higher unsaturated fat: saturated fat ratio, more emphasis on omega-3 and higher quality food sources. The mainstream version is really a bunch of … garbage (except for almonds. Almonds are awesome): processed meats, cheese, nuts and diet products, and very minimal amount of produce.

The severe lack of produce is concerning – as they provide powerful antioxidants, help our bodies to function and for long term health. Also, you need vitamins in metabolic pathways to burn fat. Diet quality has been shown to be more important than diet quantity (calories, macros) when it comes to improving metabolic biomarkers and visceral fat loss.

While saturated fat has come out of the dark side, some percentage of the population with gene alterations, need to make sure they are consuming polyunsaturated and monounsaturated fats, more than saturated fats. Additionally, those who are consuming high amounts of saturated fat, choline requirements increase. Choline is found in eggs, liver, salmon, cod, grass fed beef and those (except for eggs) are not exactly common mainstream foods. The potential side effects of overconsuming saturated fats without choline or unsaturated fats can result in fatty liver, intestinal endotoxins (lipopolysaccharides) leading to inflammation and high LDL-p.

Additionally, other ketogenic diet protocols don’t include artificial sweeteners as they have been shown to alter the gut microbiome and increase insulin (which in turn can affect ketosis). Here is more information on sweeteners on a ketogenic diet.

 

In the end…. We converted a lousy high carb diet to an equally lousy high fat diet, that we now call the Keto Diet

low fat to low carb.JPG

Mainstream “low-fat” diet

 

Mainstream Keto Diet

 

1 bowl of cereal with fat-free milk, 1 orange juice, Dannon yogurt, 1 coffee with 3 tsp sugar Bulletproof Coffee

2 eggs in 1 tbsp butter, 2 bacon strips, 1 oz cheese

Ham and low-fat cheese sandwich with white bread, 1 bag of baked lays, Nutrigrain bar, 12 oz coke 3 oz Deli meat, 1 oz cheese, low carb bread

Triple zero oikios yogurt, 2 oz flavored almonds

Grilled chicken sandwich with fries and 12 oz coke Low carb protein shake

3 Keto bomb (made with coconut oil, cocoa powder, peanut butter, stevia)

Snack: popcorn, low-fat cheese Beverages: Crystal light, diet coke
2030 kcal, 53g fat, 11g sat fat, 317 g

carbohydrates (158g sugar), 84g protein

1851 kcal, 43 g carbs, 107 g protein, 147.3g fat

16.7 grams fiber

 

Side Effects of Mainstream Keto

Bad implementation leads to a host of health issues. It also makes it difficult for researchers to study the ketogenic diet and its side effects. Could the side effects be from inducing ketosis while on a therapeutic ketogenic diet and getting all the nutrients needed? Or could it be from someone who is selecting nutrient poor fats, not drinking enough water, knows nothing about properly supplementing electrolytes, or is not eating enough fiber or micronutrients? I think that is a pretty important distinction and unless we are plowing through dietary recalls its hard to figure that out.

The source of this information was found through reading books including The Art and Science of Low Carbohydrate Living where I really learned about electrolyte supplementation, my patient experience, podcasts including Dr. Rhonda Patrick and Dr.Peter Attia, and Robb Wolf. It’s not comprehensive but it is just a summary of what I’ve read about or seen so far.

 

Side effect Poor implementation
Keto flu

Thyroid issues

Cortisol

Heart palpitation

Not enough fluids and electrolytes

Here is a great article on that

Reduced gut microbiome diversity

Constipation

Not enough fiber (veggies, not just fiber supplements), also resistant starches, too much dairy
High LDL-p Too much saturated fat: PUFA + MUFA ratio, replace some saturated fat with monounsaturated fat (especially for APOE4s)

Dr. Peter Attia goes into detail about this

Same with this article on healthline

Diet is not working (not getting in ketosis) Too high in protein

Too high in dairy and nuts

Too much artificial sweeteners

Overconsuming calories

Stress

Not sleeping enough

Here is a great summary

 

Many side effects of the ketogenic diet like the keto flu, thyroid issues, cortisol, heart palpitations could be resolved by proper implementation – such as electrolyte supplementation and fluid intake.

To learn more about potential adverse effects: Dr. Sarah Ballantyne goes over major adverse effects of long term ketogenic diet.

Is the ketogenic diet effective for weight loss?

If done correctly, if the person is a good candidate for a ketogenic diet and if they’re able to stick to the diet, then of course. A Meta-Analysis of Randomized Controlled Trials comparing very low carbohydrate ketogenic diet to a low fat diet long term found that in  13 studies the Ketogenic Diet groups achieved sometimes similar and sometimes greater weight loss compared to those assigned to the low fat diet long term.

One study examined the long-term effects of a ketogenic diet in reducing weight in 83 obese patients over 24 weeks (20% sat fat, 80% poly and monounsaturated fat). The mean initial weight of the subjects was 101.03±2.33 kg. The body weights at the 24th week was 86.67±3.70 kg. HDL increased, LDL, glucose and triglycerides decreased. The limitation of this study was that there was no control group.

This article on healthline goes into the mechanisms behind how the ketogenic diet works for weight loss (such as decreases insulin, increases satiety, reduces inflammation, decreases insulin resistance).

Aside from weight loss, several studies also show that a low carbohydrate ketogenic diet has beneficial effects on metabolic syndrome due to its ability to decrease fasting insulin, glucose, abdominal fat and inflammation moreso compared to a low-fat diet. A low fat diet typically would need to be hypocaloric to have a decrease in fasting insulin and plasma glucose (like in this study) otherwise would not have an effect on fasting insulin compared to a low carbohydrate diet. I mention insulin along with weight loss as usually with a higher BMI we see hyperinsulinemia, visceral adipose tissue and metabolic inflexibility (carbohydrate intolerance – the body just doesn’t know what to do with that fuel source, basically). So, one potential way to address the higher BMI would be to target the metabolic inflexibility.

In these studies, I’d be curious about the diet quality of the diets used in the studies and if that had any effect. I’d also want to know who was more likely to succeed on which diet and if baseline lab work could tell us if one diet was more successful for them over another. The mechanism for how ketosis works for weight loss is interesting and its not achieved during just caloric restriction. I would like to understand how a low fat diet would work for weight loss and metabolic syndrome.

 

If your goal is weight loss you can lose weight so many other ways than a “keto diet”

Previously when I would read articles that stated that, I would get annoyed because I thought those articles were being discouraging to readers who may benefit from this diet. But, I’m starting to find myself agreeing with those articles. As I have found time and time again, not many people know how to do this diet right! If the diet is not implemented correctly it can be incredibly damaging: imagine not getting the benefits of ketosis plus lack of vegetables, no fiber, and large amounts of processed meats exposed to high heat and cheese. That may even be less nutritious than what they were eating before.

The Ketogenic Diet is an advanced diet with a lot of rules, measurements and individualization. Knowing what I know about the amazing benefits of ketosis, I truly thought I would be putting many patients through this diet. I surprised myself when that didn’t happen and instead, I found myself educating my patients on the basic health foundations. A lot of my discussions were actually about getting enough water and vegetables.

This is my typical advice: Start with improving your relationship with food and understanding the role of food in health, eat within a 12 hour window, eat produce, get enough sleep, have a stress reduction technique, move every day, focus on increase the amount of nutrients in your diet, cut out empty calories and drink enough water.

It’s actually shocking how there is such a robust effect of getting even 30 minutes more sleep, adding an additional cup of vegetable to your dinner or taking a 5-10-minute walk each. This contrasts with the popular opinion that to lose weight something extremely drastic needs to be done. My patients improved biomarkers and lost weight without counting calories or macros and instead focused on drinking plenty of water, getting sleep and eating nutrient dense foods.

Once you build your foundation, then feel free to give the ketogenic diet a try (under supervision of course). Because, if you don’t get the foundation down, then it is very unlikely you will succeed on this diet. And, to be honest, you might hate it! The ketogenic diet is not all bacon, cheese and unicorns. It’s more like a slurry of olive oil, coconut milk, bone broth, spinach and fatty fish.

Remember that you don’t need to follow a ketogenic diet to get the benefits of ketosis as you can also achieve this through fasting, even perhaps a low glycemic index diet in combination with a 12 hour eating window. And, remember that you don’t have to be in ketosis all the time as there are methods that use a cyclical pattern. If it is just for weight loss then that might be a good route to take considering a lifestyle instead of a temporary fix as I think there are many benefits to becoming metabolically flexible and resilient, allowing your body to use various fuels, decrease insulin to allow processes like autophagy to occur. The ultimate goal of a diet is not to diet forever.

And, in the end I’ve had patients who successfully lost weight without being on a very low calorie low fat diet or very low carbohydrate ketogenic diet after all.

Ketogenic diet the right way: Some of my favorite resources

While I have experimented with the ketogenic diet many years ago and have educated patients through it, I am not on a low carbohydrate diet (more of a moderate low glycemic index diet depending on activity level) but I love reading about the science behind the ketogenic diet! I am constantly listening to podcasts and watching youtube videos on the latest research.

Here is a blog a Registered Dietitian wrote about her experience on the Ketogenic diet which is full of micronutrients and healthy fats, bone broth. If you are curious about if you are implementing this diet correctly there are several resources you can check out:

One Cup of Berries: Confessions of a Heavy Blueberry User

The average person eats about 2.5 cups of blueberries a year; a moderate user eats somewhere more than 3 cups a year; and a heavy blueberry user, which comprises 25% of the population, consumes more than 19 cups per year. Then there’s me. I can’t remember the last time I went a full week without eating a blueberry.

They’re absolutely delicious, fun and easy to eat and best of all, they’re a well known nutritional hero. I eat them fresh with walnuts, blend them frozen in smoothies, make blueberry almond muffins out of them, make blueberry compote for overnight oats. I eat them on a plane, on a train, in a bus in the rain…

I wasn’t always this way. I spent the majority of my adolescence and twenties in a processed food-fueled daze, downing ramen noodles, pizza, frappuccinos, and my all-time favorite: a wrap called mega-wrap, a white flour tortilla with fried chicken, cheese, ranch, and iceberg lettuce. This was supposed to be healthy (and I thought I was healthy) because the fried chicken came briefly in contact with iceberg lettuce, my one fruit/vegetable at my meals. I was so used to a continuous stream of hyperpalatable foods that, as Louis C.K. would say, at that point I probably would not have be able to taste the natural sweetness of an apple. And honestly, I was that person who put sugar on fruit.

“What we’ve done with our modern food supply is absolute insanity. It’s not even real anymore. You used to be able to give a kid an apple and they would love it. Kids can’t even taste apples anymore. Apples taste like paper to kids now.” – Louis C.K.

It wasn’t until I took my first nutrition course (nutritional biochemistry) that I discovered the effects of what increasing nutrient-dense foods, like blueberries, in my diet had on my health, quality of life, cognition, epigenetics and even mood that affected my daily life. Improving my diet made me feel better overall. You would have thought that being a Neuroscience major, I would have understood the link between diet and brain function a lot sooner. But that was hardly mentioned and was still a novel topic. Or I don’t know, I might have skipped that class because I was busy finding free food on campus after experiencing a major sugar crash. Times have certainly changed since my undergrad as we know have much more understanding on how food affects the brain. If only I knew this before!

Blueberries were my gateway super food. Blueberries got me used to eating something that wasn’t so overwhelmingly sweet and palatable. I began to enjoy the natural flavor of foods, sometimes craving the distinct mildly bitter/tartness of highly nutritious produce. It was all downhill from there: I started making kale smoothies, eating bitter Brussels sprouts,  broccoli sprouts, and grapefruits.

The Rise of the Blueberry

Blueberries have been used medicinally in Native American tribes and were believed to be sent by the Great Spirit during a great famine to relieve the hunger of their children. Blueberries were used year-round: consumed fresh when in season and were dried to preserve them for use in the winter for soups and stews. Nowadays they’re commonly discussed in news articles and health food blogs as we continue to realize that there is something very special about blueberries.

Often called a super-fruit or brain-berry, blueberries are the dominating berry. And everyone knows it. The psychographic associations of the blueberries are status-oriented, demanding and high-tech.  Thoreau calls blueberries, “that most Olympian of fruits”. Compared to its silly strawberry friend, you can count on the blueberry for getting things done.

Thank you blueberry! Now we know what antioxidants are

Compared to its silly strawberry friend, you can count on the blueberry for getting things done. Blueberries popularized the term “antioxidant”, known for zapping free radicals, and contributed to phytochemical research. In fact, blueberries are the most researched fruit. An article in The Atlantic, How People Came to Believe Blueberries Are the Healthiest Fruit by James Hamblin, describes the history of blueberry research to give us insight as to why blueberries became so popular. It is because of this research and blueberry’s association with brain health, blueberry consumption is ever growing and are the only fruits expected to continue to increase in its consumption.

When most people think of blueberries and their health benefits, the word antioxidant must come up. It’s required.

Reactive Oxygen Species (ROS) are reactive molecules with oxygen (H2O2 or O2∙). ROS are produced when we breathe, everyday metabolic functioning and are part of defenses of our immune system and play an important role in our body. Free radicals are atoms, ions or molecules that have at least one unpaired electron in their structure. These could start to react with other substances like cell membranes, fatty acids, proteins, and DNA. Under normal conditions, our body can handle ROS with antioxidants. But sometimes, it can be too much for our body to handle when there are more ROS:antioxidants, and it is implicated in many diseases.

We can make antioxidants in our body or we can get them in our diets. Polyphenols are antioxidant substances present in natural products and share the structure of pigments composed of multiple aromatic rings with hydroxyl groups. This structure allows it to scavenge free radicals and provide a myriad of health benefits including preventing cell damage and protect against several types of chronic diseases.

But, blueberries are SO much more than an antioxidant

Other than being awesome at quenching free radicals, blueberries serve many other overlooked functions, that I think they should be better known for. Blueberry derived anthocyanins can cross the blood brain barrier and congregate in regions involved in learning and memory (the hippocampus). They also help to upregulate genes that fight inflammation, improve metabolic profile, reduce mitochondrial dysfunction, produce new neurons and strengthen neuronal communication.

The anthocyanins can recognize a sequence of DNA, known as antioxidant response elements. Anthocyanins activate a gene called NRF2, which then activates genes within the antioxidant response element. NRF2 is a master regulator of many genes involved with inflammation and antioxidant activity, and neuroprotective proteins like BDNF, PGC1a and superoxide dismutase. It also decreases production of proinflammatory cytokines like TNF1, IL-1B and ROS (1).

No wonder they are constantly on the top 10 list of super foods.

Blueberries as a super food not a super fad

While there is much controversy about super foods in the dietitian community, I really like this movement of popularizing actual foods. In a world fixated on calorie and carbohydrate counting, I ultimately would like to see more individuals gravitate towards eating an actual food for nutrients instead of relying on low-calorie, low-carbohydrate “health” food-like substances and diets completely devoid of produce. This is a serious problem as only 1/10 adults consume the recommended 5 servings of fruits and vegetables a day.

One of the main arguments against calling a food a super food is that you don’t get enough nutrients from a normal dose or you can get the same nutrients in other fruits, like an apple or banana. But, that is actually not true in the case of blueberries.

Let’s take resveratrol, found in red wine for instance. You’d need to drink at least 9 gallons of red wine to even obtain the level of resveratrol needed to provide benefit! But with blueberries, you only need to eat 1 cup of blueberries a day to get enough anthocyanins (the main polyphenol in blueberries known for antioxidant and anti-inflammatory properties and is what provides its blue color). Blueberries also have a much more diverse anthocyanin species compared to other berries containing 26 different anthocyanins compared to other berries that may only have 2-3.

What happens to your cognition when you consume 1 cup of berries? What the research says.

As we grow older, there seems to be a decline in how fast we can process information and how much we can store in our working memory (WM), so we need to use more of our brain to accomplish tasks. The role of diet and exercise on preserving and improving cognitive function have recently been examined in hopes to keep our brains young and working optimally. Blueberries, especially, as it can combat inflammation and reactive oxygen species that could lead to neurodegeneration and can increase BDNF and strengthen neuronal connections (1). Whereas, the Standard American Diet has been linked to decreased cognitive performance and memory

Anecdotally, I experienced a dramatic improvement in my own ability to focus and retain information when I centered my diet around foods that have a lot of nutrients and special functions like blueberries.

But, you don’t need to just take my word for it. I found several studies using an achievable dose of 1 cup of blueberries a day (or less) examining the relationship between blueberry consumption and cognitive functioning.

 

 

Study Subjects/Duration Dose Outcome
Devore 2010
16,010 Adult Women (>70 years) from Nurses Health Study
Epidemiological Study

FFQ: 61-130 items, either <1 serving/month, 1-3 servings/month, >1 serving/week

Increased intake of berries associated with slower rate of cognitive decline by 2.5 years (using 6 cognitive tests). P-trend = 0.014
Krikorian 2010
9 Older Adults with Early Memory Decline

12 weeks

6 – 9 mL/kg Wild blueberry juice (on avg 2 cups/day)

Placebo

Improved paired associated learning (p=0.009), word list recall (p=0.04), reduced depressive symptoms (p=0.08), lower glucose level (p=0.10)
Krikorian 2016

Presented at a conference

47 Adults (Age= 68+) with MCI

16 weeks

1 cup of berries (freeze-dried blueberry powder)* or Placebo Powder
MRI: increased brain activity, 72% improvement in semantic access, 13% improvement in visual-spatial memory
Whyte 2016
21 Children (Age 7-10)

One time Acute Dose.

Placebo, 15 gram or 30 grams freeze dried wild blueberry powder.

Cognitive performance tested at 1.15, 3 and 6 hours.

Significant WBB related improvements: final immediate recall at 1.15 h, accuracy on interference task at 3h.
McNamara 2018
66 Adults (62-80 years) With Subjective Memory Decline.

24 weeks

Blueberry Powder (BB)

Fish Oil (FO)

Blueberry Powder + Fish Oil (Both)

Placebo

FO (p=0.03), BB (p=0.05) reported fewer cognitive symptoms, BB improved memory discrimination (p=0,04)
Miller 2018
37 Healthy Adults (60-75 years)

90 days

1 cup of berries (24g freeze dried powder)* or Placebo
Blueberry group had fewer repetition errosr in the California Verbal Learning Test (p=0.031) and reduced switch cost on a task-switching test (p=0,033).
  • *Note these are of the high bush variety – not the wild blueberries (wild blueberry, is known to have 3x more anthocyanin compared to the high bush variety. It is still promising to see significant improvement even with the more accessible berry.)
  • *CVLT: California Verbal Learning Test: neuropsychoogical test which can be used to access verbal memory abilities.
  • *Task Switching Test: task switching measures executive function.

In an epidemiological study conducted by Devore et al. Nurses Health Study participants, >70 year old women, filled out a Food Frequency Questionnaire. When adjusted to potential confounders, women in the highest berry consumption (>1 time per week) had a slower rate of cognitive decline by 2.5 years compared to the lowest berry consumption group (>1x per month).

Usually it would be pretty difficult to conduct double-blind randomized controlled trials (RCT) when it comes to food! However, it was done by creating a powder out of freeze-dried berries so the participants did not know what group they were in. In 4 RCTs, participants were given either ~24g freeze dried berries (equivalent to 1 cup of berries) or a placebo powder for several months.

After 90 days in Miller 2018 study, there was significant improvement in the cognitive test (CVLT) and fewer errors on an executive function test in participants. Krikorian study on individuals with Mild Cognitive Impairment, after 16 weeks, the berry group had increased brain activity on an MRI, 72% improvement in semantic access and 13% improvement in visual-spatial memory. Krikorian stated: “The other interesting result was that the blueberry-supplemented participants felt they were performing better in their everyday lives. They had a better sense of well-being and were making fewer memory mistakes and were less inefficient than they had been relative to those that received the placebo powder”.

McNamara 2018 study included a fish oil group as well but found that the participants with early memory decline who consumed the blueberry powder had a more dramatic improvement in cognitive function in 24 weeks. Blueberries had an acute effect as well. Whyte found that children who ate blueberry powder had improved accuracy on recall and interference tasks after 3 hours.

I was surprised to see that this recommendation to eat berries has not been well integrated for treatment of neurological disorders or other chronic diseases where the root cause is related to increased Reactive Oxygen Species (ROS). I’ve noticed that this is because the articles negating the blueberry power often look at studies that only take a look at its antioxidant roles, in vitro, and with supplements. But as we know now, that is not a fair assessment. Especially knowing how berries have many other effects, including epigenetic effects in addition to being a potent antioxidant.

I’m also well aware that eating more blueberries is not the only change one needs to make to prevent and treat chronic diseases. But, it would be a great starting point. Blueberries are tasty and this is easy to incorporate into the diet. Being a Registered Dietitian, I know that small, manageable changes like this is doable for patients to accomplish long term.

It is now becoming clear that the consumption of a diet rich in phytochemicals results in an improved metabolic profile, reduces inflammation and increases expression of genes that are protective. But, despite being a well known super food, the average consumption remains only 2.5 cups a year. What would happen if we strive to consume 1 cup a day, all becoming heavy blueberry users like me?

 

References:

  1. “Chapter 2- Blueberry Polyphenols and Neuroprotection ” BIOACTIVE NUTRACEUTICALS AND DIETARY SUPPLEMENTS IN NEUROLOGICAL AND BRAIN DISEASE, by RONALD ROSS. WATSON, ELSEVIER ACADEMIC PRESS, 2017