Saturated fat

Why does saturated fat raise cholesterol?

By GyroscopeUpdated November 14, 20266 sources

It slows the drain. Your liver pulls LDL out of your blood through receptors on its cells, and certain saturated fats turn those receptors down, so more LDL stays in circulation. Unsaturated fats eaten in their place turn the receptors back up. How far your own number moves is cholesterol.guide’s department.

Most people assume the cholesterol in your blood comes from the cholesterol in your food, so a high result must mean too many eggs. Your liver both sends LDL out and pulls it back in, and saturated fat works on the pulling-in side. Eggs and food cholesterol are a separate story that cholesterol.guide covers.

What we’d do: treat your cooking fat as the dial. A tablespoon of olive oil in place of a tablespoon of butter takes a day’s saturated fat down by 5.4 g, and it’s the swap with the most evidence behind it.

The model

Think of LDL in your blood as water in a bathtub with the tap always on.

1. The tap. Your liver keeps sending LDL particles out into the blood. They carry cholesterol to the cells that need it.
2. The drain. Your liver pulls LDL back out through LDL receptors on its cells. More receptors, or busier ones, means a faster drain and a lower level.
3. What saturated fat does. Long-chain saturated fats turn the receptors down, so the drain slows and the level rises. Several unsaturated fats have the opposite effect.

The model leaves one thing out. Saturated fat also seems to raise how much LDL gets made, as well as slowing how fast it drains.

The hamster experiments

Much of this was worked out in hamsters by researchers in John Dietschy’s lab in the early 1990s. In one experiment, feeding myristic acid, a 14 carbon saturated fat, cut the liver’s LDL receptor activity to 41% of normal and nearly tripled LDL. Feeding oleic acid, a monounsaturated fat, raised receptor activity to 145%.

A second experiment tested saturated fats one length at a time. The 12, 14 and 16 carbon ones turned the receptors down and about doubled LDL. The 18 carbon one (stearic acid) and the short ones from 6 to 10 carbons didn’t. A tablespoon of coconut oil carries 5.7 g of the 12 carbon kind (lauric acid), 2.3 g of the 14 and 1.2 g of the 16.

What happens in people

In a 2020 review of 16 trials, coconut oil raised LDL by about 10 mg/dL compared with non-tropical plant oils, which fits the hamster work. The trials in that review lasted at least two weeks each. How much saturated fat with high cholesterol has what to do about it.

Try:Eggs in butter, cheese, a burgerAn olive oil dayA coconut oil dayA takeout day

Add a food, or a whole day of them.

Add a food

Oils, nuts and cheeseMeat, fish and eggsMilk and yogurtSauces and spreadsTakeout and treatsBread and grainsFruit and vegetables

Cheddar cheeseParmesanAvocadoOlive oilButterAlmondsWalnutsPeanut butterCanola oilCorn oilPeanut oilSafflower oil, high oleicSesame oilSunflower oilLardCoconut oilAvocado oilBeef tallowGheeFlaxseed, groundChia seeds