Dietary Fats

Question 1

When fat enters the body, where is it distributed?

Answer 1

When fat enters the body it is distributed between liver, muscle and adipose tissue
*Liver and muscle contain small amounts of stored triglyceride (hundreds of grams), but the vast majority of whole body fat stores are located in adipose tissue.

Question 2

What are short chain fatty acids? Why are they metabolized so quickly?

Answer 2

Short chain fatty acids include the 3 carbon propionate and 4 carbon butyrate that are produced by intestinal fermentation of poorly digested carbohydrates by intestinal bacteria.
*They are not transported in chylomicrons and because they easily enter mitochondria can be quickly metabolized by the liver.

Question 3

What are medium chain fatty acids and what is their utility?

Answer 3

Medium chain fatty acids have 8-12 carbons and are used in some clinical nutritional formulae (tube feeding) for hospitalized patients because, like the short chain fatty acids, they do not require chylomicrons for transport in the plasma and so are an alternate dietary fat source that does not cause chylomicronemia.

Question 4

What kind of fatty acid chain is the vast majority of dietary fat?

Answer 4

most dietary fats are Long chain fatty acids, with 16 or more carbons.

• Saturated fats form crystals at room temperature and are therefore solid. Examples include lard, Manteca and the fat contained in red meat.
• Fatty acids that have double bonds (are un-saturated) are typically liquid at room temperature. Examples include olive oil, corn oil, and nut oils

Question 5

What is the difference between saturated and unsaturated fats?

Answer 5

• Saturated fats form crystals at room temperature and are therefore solid. Examples include lard, Manteca and the fat contained in red meat.
• Fatty acids that have double bonds (are un-saturated) are typically liquid at room temperature. Examples include olive oil, corn oil, and nut oils

Question 6

what is unique about oleic acid?

Answer 6

The C-18 mono-unsaturated fat is known as oleic acid. This fat is enriched in olive and canola oils.

Question 7

What are some pretty common unsaturated fats?

Answer 7

• N-6 fats are common in vegetable and corn oils.
• N-3 fats are common in fish and seafood.
• The C-22 n-3 fatty acid with 6 double bonds named docosahexaenoic acid or DHA is an important component of “fish oil”.
• Nut oils contain very long (C-22 to C-26) and highly unsaturated (6-8 double bonds) fats that may have unique health benefits.

Question 8

What is a “trans-fat”?

Answer 8

The chemical process of partial hydrogenation produces as what are known as trans-fats.

• In these molecules, a double bond is introduced not in a cis configuration but in a trans configuration.
• These fats are present in margarine and many processed foods.
• The problem is that naturally occurring double bonds are not in the trans configuration and the body may have trouble metabolizing these fats.

Question 9

what is the major dietary source of cholesterol?

Answer 9

Another form of dietary lipid is cholesterol.

• Dietary cholesterol primarily comes from egg yokes.
• One egg or “egg equivalent” has 300 mg of cholesterol.
• Since eggs are used in baking, the largest source of cholesterol in the diet is baked goods, in particular breads and pastries.
• The average American consumes roughly 600 mg/d of cholesterol.

Question 10

What fats are associated with beneficial health outcomes? which are associated with risk of disease?

Answer 10

monounsaturated fats and polyunsaturated fat have beneficial effects on heart disease risk.

*On the other hand saturated fat and trans fats appear to have adverse effects on CVD risk.