Human Hormones Notes: Leptin, Coristol, Insulin, Testosterone, and Triglycerides (dietary fat)

12 Jan
2011

Buzz word galore. I kept hearing (and even reading) about hormones like leptin and insulin, but I never really understood them. As I was sick last week, I finally took the time to read up on them. My notes are as follows (if anything is wrong, let me know).

Leptin

  • Leptin equates to a level of “available energy” for your body
  • Secreted by your fat cells
  • In rats, obese rats had no leptin. Inject with leptin, fat loss incurred quickly
  • Rage over leptin as the miracle weightloss
  • Contrary to rats, overweight human beings had high leptin levels
    • Overweight people had developed resistance to leptin (similar to insulin resistance)
    • Essentially the signal from leptin to brain was broken somewhere
  • Injecting overweight humans with leptin provided no real weight loss
  • Leptin scales with subcutaneous fat (higher in woman) [Inversely, insulin scales with visceral fat, higher in men]
    • Estrogen seems to increase response of leptin
  • Leptin levels do not change quickly (can take hours)
  • Males below 10% bodyfat have almost no leptin in their bloodstream
    • Women have 2-3x leptin compared to men with equal BF%
  • Leptin seems to respond directly with carbohydrate metabolism in fat cells
    • Responds to both over and under-feeding
  • After a week of dieting, leptin drops 30-50%
  • Short-term carb overfeeding can bring leptin levels up (faster than fat is gained)
    • Only responds to carb-intake. Overfeeding on fat does not produce a similar response
    • Refeeds are used for both leptin and insulin
  • Leptin basically tells your body:
    1. How much fat you are carrying
    2. How much you are eating
  • Leptin is involved in a lot of stuff, including:
    • Fat oxidation
    • Liver metabolism
    • Immune system
    • Hunger regulation
    • Libido
      • Too much body fat also impacts libido negatively due to insulin resistance
    • Possibly more
  • Levels are critical for puberty and fertility
    • Need a minimum level of fat for puberty. Childhood obesity -> higher leptin levels -> earlier puberty
    • Without enough leptin (“energy”), body decides reproduction not as important, shuts down reproductive system
      • Raising leptin brings back reproductive function without weight gain
  • Leptin is basically a safeguard from starving. With not enough “energy” body slows itself down
  • Lower levels of leptin could also impact dopamine signalling (aka increased resistance)
  • Existing fat levels matter. Losing 5% of BF at 30% BF does not trigger the same response as losing 5% of BF at 10% BF
  • Low leptin levels also make it hard to feel satiated
    • Conversely, in the short term, leptin tells your body it is full
  • As a supplement, leptin has to be injected. Pretty much impossible to get and *very* expensive
  • Best way to raise leptin is a high carb/high calorie refeed of at least two meals (eg lunch + snack).
    • Need multiple meals as leptin does not change quickly like insulin
    • The leaner you are, the more refeeds are important in restoring leptin levels
  • Zinc and Vitamin E *may* have an impact on leptin production
  • Exercise and fish oil also *may* improve leptin transport (aka sensitivity)
  • Blood triglycerides seem to be cause of resistance (lower in high fat diets)
  • Insulin (not excessive amounts) and epinephrine increase leptin transport
    • Insulin stimulates leptin release
  • Inflammation (omega 6/3 ratio) also increases leptin resistance
  • Refeeds should be high carb, moderate protein, low fat
    • Post workout is optimal time
    • Eg, Mark Sisson recommends 250-300g. Martin Berkhan targets 100-150g.
  • Short term cortisol increase can help leptin levels
  • Intermittant fasting (IF) is possibly positive – during fasting it falls, but breaking fast/refeed elevates it
    • In one study, mean leptin levels are increased. In a Ramadan study, the mean was the same
  • High amounts of fructose increases leptin resistance

Cortisol

  • Aka the stress hormone
    • Good in short-term, bad long-term
  • Used in:
    • Blood pressure
    • Regulates immune system
    • Metabolism
  • Normally peak in the morning, dips in the evening
    • Slugishness in the morning is due to low cortisol levels
    • Lack of adquate sleep decreased peak and increased dip
  • Short term elevation can:
    • Elevate mood
    • Increase leptin levels
    • Improve insulin resistance
  • Chronically elevated provides the opposite of short-term:
    • Depression
    • Reduces leptin levels
    • Water retention (diuretic)
    • Decreased testosterone
    • Indirectly promotes storage of fat
    • Muscle breakdown
    • Conversion of protein to glucose in liver
    • … and more
  • Ways to control (decreased ‘body stress’):
    • Adequate sleep
    • Exercise
    • Fasting can bring it down
    • Don’t go into too much caloric deficit
    • Do not overtrain (eg excessive cardio)
    • Antioxidants and healthy fats could also help regulate
    • Omega 3/6 balance (keep body away from inflammation)
    • Research by Bulgarians showed that workouts > 45 minutes increased cortisol
      • Bulgarians did multiple 45 minutes sessions in a day
    • Over-feeds can also decrease (by decreasing stress on body)
  • NOTE: Your body DOES need it. Just not elevated periods all the time. Only in short term peaks

Insulin

  • Used in regulation of carb/fat metabolism
    • Used to stimulate glycogen storage in liver
      • Thus lowers blood glucose level
    • Decreases protein breakdown
      • Drives amino acids into muscle
    • Directly inhibits fat mobilization from fat cells
      • Even in a fasted state insulin blocks lipolysis
  • Fear of insulin is a bit excessive
    • Needed to keep leptin levels high
  • Is raise by consumption of carbohydrates OR protein
    • Protein does not cause increase as much as carbs
      • Proten does release glucagon (carbs do not)
        • Glucagon increases blood glucose level
        • Glucagon is kind of ying/yang to insulin
    • Raises more when both consumed
    • Basically spikes when food is being absorbed and dips when none left to absorb
  • Genetics can greatly affect insulin sensitivity (upto 10x)
    • Thus while a low-carb diet may work for Person X, for Person Y a high-carb diet would be more apt
  • Working out with higher sensitivity leads to more GLUT4 activation and thus better workouts
  • Increase sensitivity with:
    • Exercise (glycogen depletion)
    • Fish Oil (EPA)
    • Fasting (glycogen depletion)
      • Thus more sensitive at breakfast
    • Cinnamon
    • Moderate alcohol
      • Even for people with type 2 diabetes
  • Insulin scales with visceral fat (higher in men) [Inversely, leptin scales with subcutaneous fat, higher in women]
  • Levels can change in minutes
  • High resistance issues:
    • Harder to build muscle
    • Libido decreases
    • Increase in blood sugar
    • Promotes fat storage
    • Fatigue
    • Increase in triglycerides
    • Increased hunger (unable to satiate properly)
    • Can cause diabetes
      • Diabetes is due to either not enough insulin (type 1) or body does not respond to insulin produced (aka resistance)
      • Over 40% of Americanos have some form of pre-diabetes suggestive of insulin resistance
    • Plaque build up in arteries
      • Causes heart disease
    • Thyroid problems (due to inablity of liver to convert thyroid hormone T4 into T3)
  • High resistance can be caused by:
    • Overeating
    • Excessive fructose/sugar (high blood sugar)
    • Glucosamine (taken for joint health) *may* also cause insulin resistance
    • Overweight (high BF%)
      • High levels of insulin do not directly cause obesity

Testosterone

  • Useful for:
    • Libido for both men and women
    • Muscular growth
    • Bone densification
    • Hair growth
    • Estrogen production (via estradiol)
  • Men have 10x compared to women
    • Women are far more sensitive
  • Mostly made in testes / ovaries
  • Decreased by:
    • Increased cortisol
    • Excessive cardio
    • Alcohol binging (10+ beers)
    • Low leptin levels (dieting)
  • Increased by:
    • Fasting
    • Exercise
      • Lifting heavy things
        • Pause at least 90s between exercises. Shorter pauses promote growth hormone more
      • Sprinting
    • Sufficient Vitamin D
    • Sufficient Zinc
    • Clean meat
      • Bull meat has roughly 35x testosterone levels compared to steer meat
    • Saturated and monounsaturated fats
    • Cholesterol
    • Limited blood sugar spikes (less than 75g of glucose)
    • Refeeds/overfeeds
  • Not affected by short-term fasting (eg leangains)
  • Moderate doses of soy do not impact testosterone levels

Triglycerides

  • Roughly 90% of the fat we consume (cholesterol is the other 10%)
    • The main component of vegetable oil and animal fat
    • Energy source and transporter of dietary fat
  • Molecularly looks *nothing* like cholesterol
  • Trans fat, monounsaturated fat, saturated fat, and polyunsaturated fat are all triglycerides
    • Trans fat – comes in refined foods
    • Monounsaturated fats: found in most food that have dietary fat (eg eggs and beef).
    • Saturated fat: found mostly in animal products
    • Polyunsaturated: liquid at room temperature, generally have a higher omega 6 to 3 ratio
  • Trans fat is not really good for you
    • The other three have both benefits and drawbacks
  • Stored and released by fat cells
  • High levels correlates with insulin resistance
  • Increased by:
    • Refined carbohydrates
      • Excess fructose (> 50g)
    • Obesity (fat storage)
  • Decrease by:
    • Moderate alcohol
    • Higher fat in diet
    • Increase insulin sensitivity
    • Exercise
    • Fish oil / omega 3
    • Vinegar
  • Excessive amounts leads to:
    • Atherosclerosis / heart disease / stroke
    • Lowered leptin transport

Sources include Examine.com, Lyle McDonald, Martin Berkhan, Mark Sisson, Stephan Guyenet, Ryan Koch, Don Matesz, Chris Masterjohn, Wikipedia, and more.

Broscience was ignored, citation was required.

Comments are closed.

top