Category Archives: Ketogenic Diet

We’re in the midst of a series exploring therapeutic ketogenic diets. Our immediate goal is to help the NBIA kids, Zach and Matthias, but most of the ideas will be transferable to other conditions – and even to healthy people who engage in occasional or intermittent ketogenic dieting for disease prevention.

Clinical ketogenic diets often produce stunted growth and bone and muscle loss. Today I want to look at this phenomenon and what we can do to avoid it.

Bone Failure and Stunted Growth

First, some data. A review of childhood epilepsy patients on ketogenic diets prescribed by Johns Hopkins Hospital doctors points out problems experienced by the children:

• Weak bones. Skeletal fractures occurred in 6 of 28 children following the ketogenic diet for 6 years; 4 children had fractures at separate locations and times. [1]
• Stunted growth. By the end of the 6 years, 23 of the 28 children were in the bottom tenth by height of their age group. [1]

Other negative effects highlighted in the review include kidney stones (7 children developed stones) and dyslipidemia (total cholesterol as high as 383 mg/dl). [1] As we’ve discussed in previous posts, these are probably caused by malnutrition. Kidney stones are usually due to deficiency of antioxidants; dyslipidemia due to deficiency of minerals, vitamins, or choline.

It’s a little hard to nail down the exact cause of the bone fractures and stunted growth because the diets were so atrocious.

First, children were told to eat calorically restricted diets to invoke the starvation response:

Calories were restricted to 75% of estimated daily needs, and fluids were calculated at 80% of daily requirements. [1]

Second, some of the children were fed formula – not real food:

[C]hildren fed only with formula all received a combination of Ross Carbohydrate-Free, Mead Johnson Microlipid, and Ross Polycose formulas to provide a nutritionally complete diet … [1]

For those keeping score, Ross Carbohydrate Free consists of soy protein isolate, high oleic safflower oil, soy oil, and coconut oil, plus vitamins and minerals. Microlipid is a safflower oil emulsion. Ross Polycose is hydrolyzed cornstarch.

(As Jake mentioned in the comments, another commonly prescribed formula is Ketocal, which consists of hydrogenated soybean oil, dry whole milk, refined soybean oil, soy lecithin, and corn syrup solids. Jake’s pithy analysis: “You might as well hold a gun to the head of the child and pull the trigger.”)

There are two problems with this diet design. First, purified diets are notoriously unhealthy; they are missing all kinds of helpful compounds found in real food. Animals do poorly on such diets, as Chris Masterjohn recently noted. Chris quotes the American Institute of Nutrition:

Purified diets without added ultratrace elements support growth and reproduction, but investigators have noted that animals exposed to stress, toxins, carcinogens or diet imbalances display more negative effects when fed purified diets than when fed cereal-based diets.

The second problem, from my point of view, is that they made little use of short-chain fats and ketogenic amino acids to make the diet ketogenic. Instead, they relied on protein and carb restriction and overall calorie restriction to force ketone production. In short, they intentionally starved the kids.

Obviously, starvation tends to produce stunted growth; this is why North Koreans are shorter than South Koreans.

I believe such starvation is totally unnecessary. Use of short-chain fats and ketogenic amino acids can trigger high ketone production even on a nourishing diet.

Nevertheless, even an awful diet is better than the best pharmaceutical drugs:

All of the parents interviewed preferred the diet over medications; 12 cited fewer side effects (such as cognitive dulling, sedation, ataxia, and behavioral problems) from medications that were successfully discontinued, and 11 cited decreased seizure frequency over medications as their primary reason. [1]

Muscle Loss

Another, closely related, problem on ketogenic diets is loss of muscle. You don’t often see bodybuilders or Olympic weight lifters who eat a continuously ketogenic diet. It can be hard to add muscle, especially on protein and carb restricted diets.

This is true even if the diet is not calorically restricted. Which brings us to a rat study [2] discussed by CarbSane in her post “Ketogenic Diet increases Fat Mass and Fat:Total Body Mass Ratio”.

The study compared two diets, a control diet and a ketogenic diet:

The ketogenic diet had more than 6 times the fat of the control diet, the same amount of protein, and no carbohydrate at all. Since protein has to be converted to glucose on zero-carb diets, this ketogenic diet is actually protein restricted. The paper confirms that the ketogenic diet operated on the margin of severe protein deficiency:

[P]reliminary experiments using a KD with 20% protein (as used in children) caused undernutrition of the rats as shown by a significant loss of weight and hair (data not shown). For this reason we used 24% protein, equivalent to that used in controls. [2]

The ketogenic diet also had lower micronutrient levels (“Ash” and “Vitamin”) than the control diet, and much higher omega-6 levels.

Rats were fed ad libitum, meaning they could eat as much as they liked; they chose to eat twice as many calories on the ketogenic diet. This suggests that the diet was protein+carbohydrate deficient.

When protein+carbohydrate intake is deficient, muscle will tend to be catabolized for protein. This causes muscle loss. Meanwhile, the starvation response – especially when more calories are eaten – tends to lead to fat mass gain.

Muscle loss and fat mass gain are exactly what happened to these rats. This is from Figure 1:

You can see in panel A that rats on the control diet weighed more than rats on the ketogenic diet. But panel B shows that rats on the ketogenic diet had more white adipose tissue (WAT). The ketogenic diet rats had more fat mass but less body mass; they had obviously lost muscle and bone mass.

I believe this is due to eating too little protein and carbohydrate. Protein+carbs were 13% on the ketogenic diet, 75% on the control diet. 13% is just too little. For humans, we recommend a minimum protein+carb intake of 600 calories per day, which is about 30% of calories for a sedentary adult. Rats kept in shoebox cages are, of course, sedentary whether they would like to be or not.

I draw two conclusions:

1.      If you’re deficient in protein+carb, you’ll lose muscle; and

2.      Losing muscle may invoke the starvation response, causing you to gain fat.

The paper did not measure length of the rats, but I would bet that the ketogenic diet rats were not only lighter, but shorter as well.

Like the children on Johns Hopkins Hospital’s diet for epilepsy, these malnourished rats experienced stunted growth.

What is the alternative?

As we discussed in the first post in this series, Ketogenic Diets, I: Ways to Make a Diet Ketogenic, there are 3 ways to make a diet ketogenic. One of them is severe protein+carb restriction, but the other two – short-chain fat consumption and supplementation of the ketogenic amino acids lysine and leucine – can generate ketosis even if substantial carbs and protein are eaten.

So it’s worth exploring: with consumption of these ketogenic nutrients, plus substantial carbs and protein, can the health impairments of clinical ketogenic diets be avoided?

Via Nigel Kinbrum comes an interesting paper [3] exploring the use of branched-chain amino acids as an adjunct to ketogenic diets for epileptic children. Most branched-chain amino acids are ketogenic, so this is a good test of my hypothesis.

The study supplemented 45.5 g leucine, 30 g isoleucine, and 24.5 g valine to 17 epileptic children on the ketogenic diet. Leucine is ketogenic, valine glucogenic, isoleucine can be either. The results:

None of our patients had a remarkable reduction in the level of urine ketosis after the supplementation of branched chain amino acids. Moreover, no exacerbation of seizures in terms of frequency or intensity was noted in any of the 17 patients of the study.

Regarding the improvement of seizures, we found 3 patients who had already achieved a reduction of seizures on the ketogenic diet to experience a complete cessation of seizures, while 2 other patients had a further reduction of seizures from 70% on ketogenic diet to 90%. In 2 other patients, the percentage of improvement with the branched chain amino acids supplementation was even greater, achieving 50% and 60% before branched chain amino acids supplementation to 80% and 90% afterward. One patient had 50% improvement (Table 1)….

According to the parents’ and teachers’ reports, improvement was noted regarding behavior and cognitive functions in 9 of 17 patients, particularly in the fields of concentration, learning ability, and communication skills with other children. It is remarkable that 1 of our children had improved so much that she is now applying to attend normal grade level for her age. [3]

There were no significant side effects; only a transient elevation of heart rate at the start of supplementation.

Importantly, supplementing these amino acids allowed more protein to be consumed for the same degree of ketosis:

The first observation we made was that by adding the branched chain amino acids, the fat-to-protein ratio of the diet changed from 4:1 to around 2.5:1 (depending on the patient’s weight) without causing any alteration in ketosis. [3]

Toxicity of Ketogenic Amino Acids

It may be possible to go higher than 45 g leucine per day. The authors acknowledge that they were being cautious in limiting branched-chain amino acid supplementation to that dose:

There is also the question of why we did not try to further increase the amount of branched chain amino acids supplementation because there were no side effects or a change in ketosis. As far as we know, it is the first time branched chain amino acids have been used in patients with epilepsy and we had to be very cautious with their administration. [3]

There is a risk of toxicity at high doses of leucine supplementation unless it is accompanied by the other branched-chain amino acids, isoleucine and valine:

Could we provide leucine alone as the most ketotic of branched chain amino acids? Providing exclusively leucine as an adjunctive treatment to ketogenic diet is impossible because it is toxic when consumed out of proportion to valine and isoleucine…. Lack of valine and isoleucine inhibits protein synthesis. The consequence is that leucine should not be consumed in large amounts without valine and isoleucine, even though only leucine promotes protein synthesis. [3]

Possibly this assessment is over-pessimistic: in rats leucine and isoleucine without valine had no significant toxicity at 5% of energy. [4] Leucine alone lacked toxicity in rat studies:

Recent studies in rats demonstrate no obvious toxicity, even with the administration of BCAA in doses that greatly exceed probable human intake. [5]

L-leucine, administered orally during organogenesis at doses up to 1000 mg/kg body weight, did not affect the outcome of pregnancy and did not cause fetotoxicity in rats. [6]

Lysine, the other purely ketogenic amino acid, is generally considered to have no significant toxicity. [7]

Considerations for the NBIA Kids

For the NBIA kids, Zach and Matthias, we want the diet to be as ketogenic as possible. This is important because glucose is unable to feed neurons due to the inability to make CoA in mitochondria and bring pyruvate into the citric acid cycle. If only ketones can feed the brain, it’s important to make as many of them as possible.

So we would like to give a lot of lysine and leucine. If we have to add other branched-chain amino acids to avoid leucine toxicity, it would be better to add isoleucine, which can be ketogenic, than valine which is only glucogenic.

The BCAA-for-epileptic-children paper [3] can help us judge safe dosages. Supplemental leucine can be at least 45 g/day, since that was give successfully to the epileptic kids. Lysine can be at least as much, since it is non-toxic. Already we’re up to around 400 calories from supplemental lysine and leucine, which is a healthy amount.

Is it necessary to give a lot of isoleucine and valine with leucine? That’s unclear. Leucine by itself may have special benefits for NBIA/PKAN kids.

Paper [5] shows an interesting set of reactions in the brain:  leucine plus pyruvate can be transformed into alpha-ketoisocaproate plus alanine in brain mitochondria. This is extremely important, perhaps, because removing pyruvate from brain mitochondria might prevent iron accumulation in the brain.

Iron accumulation in PKAN is thought to result from pyruvate buildup in mitochondria. Pyruvate attracts cysteine, because pyruvate and cysteine are normally converted to downstream products with the aid of the PanK2 enzyme that is lost in PKAN. With the loss of PanK2, pyruvate and cysteine build up, and the cysteine chelates iron, trapping it in brain mitochondria.

If leucine can remove pyruvate from brain mitochondria, it may also diminish cysteine levels and therefore reduce iron trapping in mitochondria. The iron buildup that is so debilitating might be prevented or mitigated.

Conclusion

I believe the extreme limits on carb and protein intake in conventional clinical ketogenic diets are responsible for their growth stunting, muscle destroying, fattening effects.

In order to supply sufficient protein and carbs while maintaining ketosis, it is necessary to provide ketogenic short-chain fats and amino acids.

Clinical testing of such supplemented diets has so far produced encouraging results. Providing supplemental amino acids to epileptic children on ketogenic diets improved their health and allowed them to maintain ketosis with higher protein intake. Seizure frequency was reduced even as side effects diminished.

Personally, I wouldn’t attempt a long-term ketogenic diet without the aid of coconut oil (or MCTs), lysine, and the branched chain amino acids.

For the NBIA/PKAN kids, it seems that the amino acid supplements should be some mix of lysine, leucine, isoleucine, and valine, with the isoleucine and valine included solely to reduce leucine toxicity. The optimal amount of isoleucine and valine should be smaller than is found in branched-chain amino acid supplements, since leucine by itself may help prevent iron accumulation and increase ketosis. Also, one rat study [4] indicates that isoleucine alone, excluding valine, might be enough to relieve leucine toxicity. Excluding valine would increase the ketogenicity of the supplement mix.

I think the NBIA/PKAN kids will need to experiment with primarily lysine and leucine, and secondarily isoleucine and BCAA supplements, to see what mix works best for them.

References

[1] Groesbeck DK et al. Long-term use of the ketogenic diet in the treatment of epilepsy. Dev Med Child Neurol. 2006 Dec;48(12):978-81. http://pmid.us/17109786. Hat tip CarbSane.

[2] Ribeiro LC et al. Ketogenic diet-fed rats have increased fat mass and phosphoenolpyruvate carboxykinase activity. Mol Nutr Food Res. 2008 Nov;52(11):1365-71. http://pmid.us/18655006. Hat tip CarbSane.

[3] Evangeliou A et al. Branched chain amino acids as adjunctive therapy to ketogenic diet in epilepsy: pilot study and hypothesis. J Child Neurol. 2009 Oct;24(10):1268-72. http://pmid.us/19687389. Hat tip Nigel Kinbrum.

[4] Tsubuku S et al. Thirteen-week oral toxicity study of branched-chain amino acids in rats. Int J Toxicol. 2004 Mar-Apr;23(2):119-26. http://pmid.us/15204732.

[5] Yudkoff M et al. Brain amino acid requirements and toxicity: the example of leucine. J Nutr. 2005 Jun;135(6 Suppl):1531S-8S. http://pmid.us/15930465.

[6] Mawatari K et al. Prolonged oral treatment with an essential amino acid L-leucine does not affect female reproductive function and embryo-fetal development in rats. Food Chem Toxicol. 2004 Sep;42(9):1505-11. http://pmid.us/15234081.

[7] Tsubuku S et al. Thirteen-week oral toxicity study of L-lysine hydrochloride in rats. Int J Toxicol. 2004 Mar-Apr;23(2):113-8. http://pmid.us/15204731.

I was going to write a single post about how to implement a therapeutic ketogenic (ketone-generating) diet.

But then I thought it was worth spelling out issues in some detail. There are various ways to make a diet ketogenic, and different ways are appropriate in different diseases. Also, different diseases may call for a different balance between three criteria:

1)      Safety. Does the diet generate side effects?

2)      Therapy. Is the diet as curative as it can be?

3)      Pleasurability and practicality. Is the diet unnecessarily expensive, unpalatable, or boring?

I soon realized that with so many factors affecting diet design, it would be hard to fit everything into a single post. So I’m going to split up the discussion into parts. Today I’ll look at the various ways to make a diet ketogenic. On Tuesday I’ll look at how to design a diet for Kindy’s NBIA kids. We’ll look at what they’re eating now, and consider ways they might be able to improve their diets further – and, hopefully, get further improvements in health, longevity, and function.

Maybe we’ll look at some other diseases after that, or maybe I’ll just move on to the lemon juice series I’ve been planning. The lemon juice and acid-base balance issues will fit in nicely since kidney stones and acidosis are risks of ketogenic diets and lemon juice relieves those risks.

So: how can we make a diet ketogenic?

What Is a Ketone?

The liver is responsible for making sure that the body (but especially the brain and heart) have access to a sufficient supply of energy from the blood. To fulfill that responsibility, it manufactures two energy substrates – glucose and ketones – and exports them into the blood as needed.

The most important ketones are acetoacetic acid and beta-hydroxybutyric acid.

Ketones are water-soluble small molecules. They diffuse throughout the body into cells, and are taken up by mitochondria and oxidized for energy.

Ketones are especially important to neurons, which can only consume glucose or ketones. So if something is wrong with glucose metabolism, ketones can be the sole usable energy source of neurons. (Other cell types, but not neurons, burn fats.)

Manufacture of Glucose and Ketones During Starvation

While preparing this post, I was surprised at how long it took for doctors to appreciate that ketones are an acceptable alternative energy source for the brain. The realization that the brain doesn’t perpetually rely on glucose during starvation apparently didn’t sink in until 1967!

The use of prolonged starvation for the treatment of obesity has posed a fascinating problem; namely, that man is capable of fasting for periods of time beyond which he would have utilized all of his carbohydrate resources and all of his proteins for gluconeogenesis in order to provide adequate calories as glucose for the central nervous system.

This study was designed to clarify the apparent paradox, and it was found that beta-hydroxybutyrate and acetoacetate replace glucose as the brain’s primary fuel during starvation. [1]

This makes it a bit easier to understand why ketogenic diets have not yet become standard therapies for neurological diseases. Epileptics caught a lucky break – the ketogenic diet was already in use for epilepsy in the 1920s. The ketogenic diet’s therapeutic potential for other neurological disorders probably couldn’t have been appreciated until after 1967, and by then medicine had turned its back on dietary therapy.

But back to ketones. During starvation, glucose and ketones have to be manufactured from body parts. The body’s resources include:

• Glycogen – a storage form of glucose. However, glycogen supplies are minimal.
• “Complete” protein – a mix of amino acids similar to that found in animal meats.
• Long-chain fats – fatty acids 14-carbons or longer in length, attached to a glycerol backbone as either triglycerides or phospholipids.

During starvation, different raw materials end up as different energy substrates:

• Glycogen can be used to make glucose but not ketones. So glycogen converts 100% to glucose.
• Protein is broken down into its constituent amino acids. Some amino acids can become glucose but never ketones; some can become either; some can become ketones but glucose. “Complete” protein usually found in the body typically converts 46% to ketones, 54% to glucose. [UPDATE: Actually, this is incorrect. As Tony Mach points out in the comments, complete protein converts 20% to ketones, 80% to glucose. The 46-54 ratio is the contribution to Wilder’s ketogenic ratio, see below.]
• Triglycerides and phospholipids are broken up into their constituent parts. The fatty acids can make ketones but not glucose; the glycerol backbones can make glucose but not ketones. Typically, 10-12% of energy from a triglyceride is in the form of glycerol (which has the potential to become glucose) and 88-90% is in the form of fatty acids (which have the potential to become ketones).

As we note in the book, during starvation the body is cannibalizing tissues that are roughly 74% fat, 26% protein by calories. Due to the preponderance of fat, starvation is highly “ketogenic” (ketone generating). The 26% of calories that are protein generate roughly equal amounts of ketones and glucose, but the 74% of calories that are fat generate only ketones.

This doesn’t mean that during starvation ketones are 87% of energy and glucose 13% of energy. Most of the fats are burnt directly for energy without conversion to ketones. But a fair amount of fats are diverted into ketone production, and ketones are abundant during starvation.

A Ketogenic Diet Using “Body Part Foods”

If your diet could include only compounds found in the body – glucose, complete protein, and long-chain fats stored as triglycerides or phospholipids – then we can use the above numbers to estimate the “ketogenic potential” of the diet.

I have to credit commenter “Cathy” at the PaNu Forum for this next part. Kindy posted a question about the ketogenic diet for NBIA on the PaNu Forum in October 2010, and Cathy left an informative comment:

The ketogenic formula was originally developed by Wilder at the Mayo clinic in the 1920’s. By googling WILDER KETOGENIC FORMULA, I found a link to the book “The Ketogenic Diet: A Treatment for Epilepsy” published in 2000. Quite a bit of the book is available for reading online; here is the URL

.

On page 36 of this book is Wilder’s formula for the ketogenic potential of a diet:

This formula basically treats all fats as triglycerides of long-chain fatty acids, and protein as “complete” protein with a typical mix of amino acids. It makes a ratio of the ketone precursors to the glucose precursors.

Wilder’s “ketogenic ratio” was used by Dr. Richard Bernstein in his Diabetes Solution to help people appraise the ketogenicity of a diet. A ratio below 1.5 signifies a minimally ketogenic diet; the higher the ratio goes above 1.5, the more ketones will be generated.

Other Dietary Ketone Precursors

If you’re not starving, you have the opportunity to eat foods that are not components of the body, and that are more ketogenic than “body part foods.”

Specifically, you can eat:

• Short-chain fats such as are found in coconut oil.
• A mix of amino acids that is not “complete,” but is biased toward the ketogenic amino acids.

If you do this then your diet will be more ketogenic than Wilder’s formula would suggest.

Eating these foods may be advantageous. For instance, suppose you want to eat enough carbs to avoid “zero-carb dangers” such as mucus deficiency. At the same time, you want to generate abundant ketones to nourish the brain. You can achieve both by eating carbs for glucose, but also eating short-chain fats and ketogenic amino acids to make ketones.

So let’s look at why these foods are so effective at producing ketones.

Amino Acids

The main metabolic process which converts one metabolic substrate into another is called the citric acid cycle, tricarboxylic acid (TCA) cycle, or Krebs cycle.

The TCA cycle looks like this (blue arrows):

The passage from succinyl CoA to fumarate is where ATP is made. The cycle can be fed in several ways:

• By pyruvate which is an intermediate produced in glucose metabolism;
• By acetyl CoA which is an intermediate produced by ketones or fatty acid oxidation;
• By amino acids which can enter the TCA cycle at various points.

The green boxes show glucogenic amino acids entering the cycle. The white boxes show ketogenic amino acids that are made into either acetyl CoA or acetoacetyl CoA and thence can either leave as ketones (via HMG-CoA) or enter the cycle by conversion of acetyl CoA to citrate.

The crucial takeaway, as far as this post is concerned, is the distribution of amino acids among green and white boxes:

• Leucine and lysine appear only in white boxes, not in green boxes. They are purely ketogenic.
• Isoleucine, tryptophan, phenylalanine, and tyrosine appear in both green and white boxes. They can be either ketogenic or glucogenic.
• The other amino acids appear only in green boxes and are purely glucogenic.

So if the diet is rich in leucine and lysine, but poor in glucogenic amino acids, then it will be highly ketogenic.

Short-Chain Fats

Fats are made into acetyl CoA. Acetyl CoA can either enter the TCA cycle or be converted to ketones. What decides which way it goes?

One important factor is whether the cell has enough ATP. If the cell has plenty of ATP then it won’t allow the TCA cycle to make any more, and the TCA cycle gets stuffed with succinyl CoA and then with all the other intermediates in the pipeline behind it.

Once the TCA cycle is full, acetyl CoA no longer enters the cycle and instead leaves as ketones.

Long-chain fats can follow this route, but not terribly easily. They have alternatives:

• Long-chain fats can serve as structural molecules in cell membranes throughout the body.
• Long-chain fats can be stored in adipose cells.
• Long-chain fats can be burned by cells throughout the body, and transported to cells that need them.

These factors mean that you have to eat a very large amount of long-chain fats before you produce substantial ketones.

Short-chain fats (12 carbons or less in length; often called medium-chain) are different. Short-chain fats do not appear in cell membranes and are not stored in adipose tissue (except for a little 12-carbon fatty acids). Rather than being transported throughout the body, they are shunted to the liver for disposal.

This means that if you eat a lot of coconut oil (which is 58% short-chain fats), you deliver a lot of fat to the liver for disposal. The disposal process for fat is conversion to acetyl CoA followed by either burning in the TCA cycle or conversion to ketones.

After a big cup of coconut oil is delivered to the liver, the liver’s ATP levels are quickly saturated. The TCA cycle is stuffed and the liver will dispose of the coconut oil by making ketones.

It will do this whether the rest of the body needs the ketones or not. The liver wants to get rid of the coconut oil, and it does it by making ketones whether the rest of the body wants them or not.

Summary

So we have three ways to make the diet ketogenic:

1)      Make Wilder’s “ketogenic ratio” high by eating a lot of fat, very few carbs, and not too much protein.

2)      Supplement with the ketogenic amino acids lysine and leucine.

3)      Supplement with coconut oil or another source of short-chain fats.

If we do (2) or (3), then the diet can be ketogenic even if it has a fair number of carbs.

So now we have an arsenal of ways to generate ketones. We have to look at diseases and diet risks to figure out which way of making the diet ketogenic is optimal.

I’ll look at that next week.

References

[1] Owen OE et al. Brain metabolism during fasting. J Clin Invest. 1967 Oct;46(10):1589-95. http://pmid.us/6061736.