Saturday, September 28, 2013

Plant-Based Diet Lowers Cholesterol - A Lot

Rip Esselstyn, author of The Engine 2 Diet, describes the story of 42-year-old Nick Gravina, "one of the fittest firefighters in the South Metro, Colorado, fire department":
"[Nick] was a total beast at the Firefighter Combat Challenge, a timed competition that involves climbing a 50-foot tower with five flights of stairs carrying a 42-pound roll of fire hose, descending and slamming a sledgehammer into a 160-pound metal beam until it moves 5 feet, pulling a charged hose line 75 feet, opening the nozzle and flowing water and hitting a target, and dragging a 175-pound dummy 106 feet to the finish line. Nick was able to do all this in less than 1 minute and 35 seconds, all the while wearing full gear and breathing air from a 30-pound Air-Pak on his back!

One day, Nick ... started to feel some chest pain that he thought was just a bad case of indigestion, but it was painful enough that he alerted his crew, who immediately hooked him up to the heart monitor to get a look at his heart. The paramedic saw an abnormal rhythm and called an ambulance just as Nick's heart stopped beating and he stopped breathing - he was, basically, dead. ... The ambulance rushed him to the hospital. ... After one hour of CPR and 18 shocks to his heart, Nick's doctors were able to remove a blood clot from his heart, saving his life."
Nick, who Esselstyn said, "was a great athlete, but he'd always eaten whatever he wanted, thinking he could burn everything off," went on a low-fat, whole food, plant-based diet (The Engine 2 (E2) Diet, which has no calorie limit).
"Since going on the E2 diet, Nick's total cholesterol has come down to 83 mg/dl, his LDL is 35 mg/dl, he's leaner than he's ever been, and he feels empowered with the knowledge that he and his food choices now control his health destiny."
Nick's heart attack was in March 2012. Esselstyn's book, My Beef With Meat, where he relates Nick's story, came out in May 2013. So, Nick accomplished his cholesterol-lowering feat in about a year. We aren't told Nick's cholesterol prior to his heart attack.

Nick's total cholesterol of 83 md/dl and his LDL of 35 mg/dl are not common in the US. Total cholesterol here hovers around 200 mg/dl, and LDL around 120 (Trends In Lipids And Lipoproteins In US Adults, 1988-2010, JAMA, 2012).

But what is common is not necessarily what is healthful. The Cleveland Clinic gives the goal for total cholesterol at 75-169 mg/dl for those age 20 and younger, 100-199 for those over age 21. The National Cholesterol Education Program says that a "desirable" total cholesterol is less than 200 mg/dl, and an "optimal" LDL is less than 100 mg/dl. American's cholesterol levels are struggling to meet these goals. Nick's levels meet these goals with substantial margins.

Goals aside, what level of cholesterol do we actually need to function? Brown and Goldstein1 say
"The LDL receptor studies lend experimental support to the epidemiologists’ suggestion that the levels of plasma cholesterol usually seen’ in Western industrialized societies are inappropriately high (9). This support derives from knowledge of the affinity of the LDL receptor for LDL. The receptor binds LDL optimally when the lipoprotein is present at a cholesterol concentration of 2.5 mg/dl (28). In view of the 10 to 1 gradient between concentrations of LDL in plasma and interstitial fluid, a level of LDL-cholesterol in plasma of 25 mg/dl would be sufficient to nourish body cells with cholesterol (118). This is roughly one-fifth of the level usually seen in Western societies (Fig. 16 and ref. 119).

Several lines of evidence suggest that plasma levels of LDL-cholesterol in the range of 25-60 mg/dl (total plasma cholesterol of 110 to 150 mg/dl) might indeed be physiologic for human beings. First, in other mammalian species that do not develop atherosclerosis, the plasma LDL-cholesterol level is generally less than 80 mg/dl (Fig. 16 and ref. 120). In these animals the affinity of the LDL receptor for their own LDL is roughly the same as the affinity of the human LDL receptor for human LDL, implying that these species are designed by evolution to have similar plasma LDL levels (9,119). Second, the LDL level in newborn humans is approximately 30 mg/dl (121), well within the range that seems to be appropriate for receptor binding (Fig. 16). Third, when humans are raised on a low fat diet, the plasma LDL-cholesterol tends to stay in the range of 50 to 80 mg/dl. [LDL] only reaches levels above 100 mg/dl in individuals who consume a diet rich in saturated animal fats and cholesterol that is customarily ingested in Western societies (116,122)."
This is interesting. They explain how LDL rises. First, the LDL receptor fills up:
How might a diet rich in animal fats and cholesterol elevate the plasma LDL-cholesterol level? ... As the plasma LDL level rises, the receptors become saturated. This saturation of receptors sets an upper limit on the rate at which LDL can be removed efficiently from plasma (123). ... Once the receptors become saturated, the rate of removal of LDL can be accelerated only by an increase in clearance by non-receptor pathways that operate at low efficiency. In order to drive these alternate pathways, the LDL level must be quite high (99).
And then, holy moly:
"When excess dietary cholesterol accumulates in the liver, the liver responds by decreasing the production of LDL receptors."
So, it isn't just the input of LDL (via consumption and endogenous production) that makes cholesterol go up, but the inability to clear it.

Nick's LDL of 35 falls within Brown and Goldstein's range of 25-69 mg/dl. His total cholesterol of 83 falls within the Cleveland Clinic's range of 75-169 mg/dl (age 20 and younger).

There is clearly a benefit to eating a low-fat, whole food, plant-based diet that goes beyond what athletic prowess can deliver.

1 Michael S. Brown and Joseph L. Goldstein were awarded the Nobel Prize in Physiology or Medicine 1985 for their discoveries concerning the regulation of cholesterol metabolism:
- A Receptor-Mediated Pathway For Cholesterol Homeostasis, Nobel Lecture, Brown MS and Goldstein JL*, December 1985,
- A Receptor-Mediated Pathway For Cholesterol Homeostasis, American Association for the Advancement of Science, Brown MS and Goldstein JL, April 1986

Thanks to Healthy Longevity for the link to Brown and Goldstein.

1 comment:

RB said...


You might like this Rip Esselstyn TEDx talk.