"This article was originally published at HVMN."
Beta-hydroxybutyrate (or BHB) is topic often discussed in keto
circles, but one that might seem foreign to an outsider.
Whether it’s talk of the ketogenic diet or ketosis or exogenous ketones, understanding BHB is essential
to developing a well-rounded knowledge of keto. It can be a confusing topic,
but we’ll demystify BHB by explaining it from several angles.
In this piece, we analyze the science behind BHB, what it does,
where it comes from, and why it’s important for optimizing your keto goals
(whatever they may be).
What Exactly is BHB?
It’s always good to start at the chemical
description. Beta-hydroxybutyrate is also known as beta-hydroxybutyric acid or
3-hydroxybutyrate. It’s an organic compound with the formula C4H803.1
Under the umbrella of ketones in human metabolism, BHB is
considered one of the three “physiological” ketone bodies produced and burned
in our cells. But opening an organic chemistry textbook, BHB won’t fit the true
criteria of a “ketone.”
A ketone is defined as having carbonyl carbons (carbon joined to
oxygen with a double bond) bonded to two other carbon atoms. BHB has a carbonyl
carbon, but it’s only bound to one other carbon atom.
The chemical structure of a
ketone: a carbon molecule joined to an oxygen molecule with a double bond
The chemical formulas of the
three main ketone bodies: AcAc, Acetone and BHB (which doesn't fall under the
traditional definition of a ketone)
Despite this technicality, BHB is still
considered one of the three ketone bodies because this family of metabolites
are closely related and affect the body similarly. BHB levels increase in the
brain, heart, muscle, liver and other tissues when restricting calories,
fasting, following a ketogenic diet, or even as a result of exercise.2
Ketosis Recap
Before exploring BHB further, let’s develop a basic understanding
of what ketosis is, and how it works.
Ketosis marks the presence of ketones in the
body, usually at >0.5mM. Ketosis is usually achieved through endogenous
ketones, meaning ketones are produced naturally by the body as a result of diet
or fasting. You can read more deeply about the nuances of ketosis here.
When we eat carbohydrates, they’re converted
into glucose in the blood. Glucose is then used as our brain’s fuel source–but
when carb intake is restricted (like when following a low-carb, high-fat ketogenic diet) the brain requires an alternate
fuel source.
While most other organs in the
body can use fat as fuel, the brain can’t; however, the brain can use ketones
for energy.
So the body turns fat into ketones to be used
both as body and brain fuel. Ketones can provide up to 60% of the energy needed
by the brain.3
Ketogenic metabolism produces three different types of ketones:
·
Acetate (Acetone)
·
Acetoacetate (AcAc)
·
Beta-hydroxybutyrate
(BHB)
Acetone is the least abundant, produced in much
smaller amounts, and is usually exhaled through the lungs rather than being used
as fuel.4 Acetoacetate
is part of the metabolic pathway whereby humans make and use ketones, but it
tends to be found in the blood at lower levels than BHB.
BHB is the predominant ketone body in the blood.
Did you know there are different types of ketones?
Many companies cite the benefits of ketone esters for a ketone
salts, but they couldn’t be more different. Salts, esters, and the multiple
kinds of esters–it can be confusing. Our team is conducting research on each
compound to clarify it all for you. Subscribe to see how we set the record
straight.
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How is BHB Made?
It happens two different ways.
Endogenous BHB
Endogenous ketones are produced by the body
naturally through a low-carb diet or fasting. The process for
creating endogenous BHB is called ketogenesis.
The ketone produced in a fasted state via ketogenesis is
Acetoacetate (AcAc). Fatty acids are broken down to produce acetyl CoA, which
then undergoe a chain of reactions to eventually form AcAc.
In the liver, the BHB-dehydrogenase enzyme reduces AcAc to form
BHB. This BHB then goes on to be used as fuel for the body as the primary
circulating ketone body.
The best way to increase production of endogenous BHB is to reach
a state of nutritional ketosis by reducing carbohydrate intake or fasting.
Exogenous BHB
Priming the body to trigger endogenous ketone
production takes time and effort. To provide a quicker alternative to natural
ketone production, there are exogenous BHB ketones which can be consumed
through supplements. Exogenous ketones come from an external
source since they’re not produced in the body.
There several different options when considering which exogenous
ketone supplement to take.
MCT Oils: Medium chain
triglycerides (MCT) don’t contain BHB, but consuming MCT oils can moderately
raise BHB. They contain fat molecules that are easily converted into BHB.
MCTs require more processing inside of the body compared to other
types of exogenous ketones and therefore take longer to get a body into
ketosis. They’re also calorie-dense (a natural source of MCT is coconut oil),
so it may be ultimately counterproductive to rack up calories just to elevate
ketones.
Ketone Salts:
Ketone salts are a compound consisting of a mineral ion, such as sodium (Na+),
potassium (K+), and BHB. The compound is held together by ionic bonds, but when
consumed, the salt dissociates into free Na+, K+, and BHB. Thus, BHB blood
concentrations are raised, but only to levels of 0.5 - 1 mM.5
Combining sodium and potassium to bond BHB is cost-effective, but
it can lead to excessive sodium consumption to attain the desired level of
blood ketones. An advantage of ketone salts is that they’re high in
electrolytes; so they can replenish electrolytes lost in urine while on the
ketogenic diet.
Ketone Esters:
Ketone esters are composed of a raw ketone molecule (BHB or AcAc) bound to a
ketone precursor using an ester bond (butanediol or glycerol).
An example is HVMN
Ketone–the world’s first ketone ester drink. Deeper and faster
ketosis can be obtained from ketone ester drinks, with levels reaching 3 - 5
mM–several times higher than ketone salt drinks.5
Benefits of HVMN Ketone also include:
·
Increased cognitive
performance: HVMN Ketone improved maze solving time by 38% in an animal
experiment6
·
Decreased food
cravings/increased satiety: HVMN Ketone decreases hunger and ghrelin5
·
Improved athletic
performance and endurance: HVMN Ketone improved athletic performance in elite
cyclists7
·
Lowered blood sugar:
HVMN Ketone decrease blood sugar in response to a meal and lowered blood lipids5,8
For athletes, in particular, using exogenous ketone
bodies like HVMN Ketone allows them to receive some of the benefits of ketosis
without the time spent fasting and dieting to achieve nutritional ketosis.
Benefits of BHB
Having discussed BHB, and how it gets into the body, it’s time to
look at its benefits.
BHB Provides Natural, Clean Energy
As the main ketone body, BHB acts as an energy source. Through
ketolysis, ketones are broken down using aerobic respiration inside the
mitochondria. Ketolysis occurs throughout all tissues in the body except the
liver (because the liver doesn’t contain one of the key enzymes for ketone
oxidation).
When BHB enters the mitochondria of the cell, it’s converted to
acetoacetate, after which it undergoes a reaction where CoA is added. The
result is acetoacetyl-CoA, which is cleaved to form acetone and acetyl-CoA.
The acetyl-CoA progresses into the Krebs cycle
and results in the production of ATP, which as you know, is the energy needed
for the cellular functions.9
Ketones are clean-burning because they reduce the production of
potentially harmful reactive oxygen species (ROS) inside cells. They’re also
able to scavenge (clean up) ROS produced by other metabolic processes.
BHB is Powerful Brain Fuel
BHB easily crosses the blood-brain barrier
(crossing from the peripheral circulation to the central nervous system).2 While
BHB can provide energy for the body, it’s particularly well-suited to provide
energy for the brain.
BHB isn’t just an energy source for the brain–it
has other effects which promote brain health. BHB can trigger the release of
chemicals called neurotrophins, which support neuron function and synapse
formation. One of these neurotrophins is called BDNF (brain-derived
neurotrophic factor), which is a protein in the brain associated with cognitive
enhancement, alleviation of depression and reduction of anxiety.10
A 2017 study that injected rats with intravenous
ketones, then subjected them to stressful situations, found that BHB reduced
stress-induced neuroinflammation.11
This combination of energy
provision, neurotrophins and anti-inflammatory benefits illustrate that BHB has
broad-spectrum effects that might improve the pathology of various neurological
conditions.
Increased levels of BHB in the body were found
to be associated with greater cognitive performance through better performance
in memory recall tests12 on
a study of 20 subjects with Alzheimer’s disease or demonstration of a mild
cognitive deficit. Similarly, BHB ketone esters helped to reverse symptoms of
Alzheimer's Disease in one clinical case study.13 More
research in humans is needed, but the various hypotheses are backed up by
strong animal data.
BHB is the Easiest Ketone to
Measure Accurately in the Blood
For those looking to maintain ketosis, testing should be regularly undertaken to
verify the presence of ketones in the blood, breath or urine.
The three ketones are measurable as follows:
·
BHB: in the blood
·
Acetone: in the breath
·
Acetoacetate (AcAc): in
the urine
In blood, BHB is the most prevalent of the ketones. It’s widely
used to measure ketone levels because it is present at far higher
concentrations than Acetone and Acetoacetate and it exists outside the cell,
making it both easy to measure and accurate.
A handheld blood glucose monitor is the most common measuring
tool, as it has the capability to also measure blood ketone levels. The test is
akin to a diabetic testing blood sugar with a finger prick.
Optimizing Keto Goals with BHB
BHB plays a pivotal role in the world of ketones and ketosis. Knowledge
about BHB will help further map the keto landscape, and allow anyone to plot a
course to achieve their goals.
It’s your body–knowing how it works can empower you to make the
best decisions for it.
We’re actively investigating BHB. Be first to know the results.
HVMN is working with
several research organizations, conducting human studies on the benefits of
BHB. Everything from sports performance to mental benefits to medical use cases
are being explored. Subscribe to be on the cutting edge of that science.
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