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NEAT F A T S I N H U M A N N U T R I T I O N P n i L i P L. WHITE, S C . D . , S E C R E T A R Y

I. Functions of Fat

A. Dietary _I Fat

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Fat i s a concen5rated source of calories, thereby serving t o reduce the bulk of food needed t o supply calor ic requirements. This becomes of greater significance a s calor ic requirement increases . Fat increases the pa la tab i l i ty and acceptabi l i ty of food.

Bt is a c a r r i e r and/or source of fat-soluble nutrients, in- cluding vitamins A, D, and E, l l no le i c acid.

Fat reduces the emptying time of the stomach with cer ta in attendant advantages, e,g,, satiety, improved digestion, mucosal protection.

€3. bktabolic Amctions --- 1. Fat increases the efficiency of food u t i l i za t ion , including the

conservation of thiamine.

2. Fat is needed f o r growth and f o r maintenance of t i s sues and i n cer ta in l i p i d secretions.

Fat serves a s spec i f ic fuel f o r t h e metabolism of many tissues. 3 .

11. Animal Fat i n Today's Diet - A. Consumers demand leaner meats with no change i n quali ty.

1. Wre a ref lect ion of calor ie consciousness than of concern over cardiovascular disease.

B. There is considerable research interest i n the metabolism of animal f a t s re la ted t o cardiovascular disease.

1. btabol i sm of individual fatty acids.

2. Bktabolism of short, medium, and long chain t r iglycer ides i n presence and absence of cholesteml.

Quantitative studies of effect of saturated f a t t y acids i n human physiology.

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4. Evaluation of prac t ica l significance of P/S ra t ios .

5. ECfect of dietary cholesterol on blood l ip ids .

6. Effect of dietary f a t on stored and circulat ing human f a t .

There a re a number of carefully conducted studies underway t o assess the e f f ec t of controlled diets on blood f a t s and on cardiovascular disease incidence. Relatively large numbers of people a re involved. The purpose of these studies is t o deternine whether adherence t o d i e t s designed t o provide l e s s saturated fa t (animal f a t s ) and more polyunsaturated f a t (vegetable fats) than usually consumed in t h i s country w i l l bring about suf f ic ien t reduction of cholesterol and possibly reduce the r i sk of heart disease. In the more sophisticated st:rdies blood l ipids i n addition t o cholesterol a re measured, but the largest studies s t i l l use cholesterol a s the biochemical parmeter of dietary success. The s tudies a r e designed t o tes t the hypothesis that "normal" or low cholesterol levels will prevent a delay, lessen the severi ty of, o r hasten the recovery f r o m heart disease.

The group studies have not been underway for suf f ic ien t time t o const i tute a t rue test of the hypothesis; however, some important experi- ence has been gained. has been achieved in most cases, and the diets have been found t o be pmc- t i c a l f r o m a gourmet viewpoint. In some c a ~ e s , there i s a suggestion that subjects i n the studies have had less cardiovascular disease development than would have been predicted, However, the question of appropriate group comparisons and controls cas t s doubt on the significance of these ear ly reports

S t a t i s t i c a l l y s i m i f i c a n t lowering of cholesterol

There a r e a number of recent developments that would j u s t i e a somewhat detai led discussion of the diets currently in use o r proposed. The group studies are underway i n New York City and i n Boston, Chicago, Minneapolis, Oakland, and Baltimore. of experts camying out EI very large cooperative study. American Heart Association recently released a fat-controlled diet booklet f o r pat ient use, and the American Ikdical Association published a report t o the physician on the regulation of dietary f a t .

Dr. Imine Page is direct ing a team In addition, the

The diets used i n the group s tudies have a great deal i n common. Saturated f a t is reduced f r o m a usual. da i ly intake of about 58 gm. t o 20 - 30 gn, Sources of polyunsaturated f a t t y acids are provided t o y ie ld from 20 - 45 grams of l i no le i c acid depending upon the t o t a l number of calories. Although the t o t a l amrrunt and the kind of fat i n the diets a re important, a qual i ta t ive evaluation can be obtained by a consideration of the r a t i o of l i no le i c acid o r polyunsaturated fa t ty acids ,to saturated f a t t y acids. In the usual American diet the r a t i o i a about 0.3, i.e., only 1/3 of the fa t is from l ino le i c acid. A l l of the experimental d i e t s s t r i v e fo r a t l e a s t a 1 t o 1 r a t i o and some go as high as 2 t o 1. i n passing that some investigators suggest that a t least 50 gm. of l i no le i c acid should be provided i n the special diets.

It should be noted

Another feature c o m n t o all of the diets is the rather complete elimination of dairy f a t s . allowed; only a few cheeses are permitted.

No whole milk, cream, but ter , o r ice cream is Non-fat milk may be used,

55 . however. are a l so s t r i c t l y controlled. t o reduce the t o t a l amount of saturated f a t s , of the fa t consumed i n the United States (40 @./day); meats, paultry, fish, and eggs provide 275 (39 gm./day). of saturated f a t s is t o be reduced, the v i s ib l e sources of f a t must go. Only the leanest meats i n res t r ic ted quant i t ies a re allowed. Poultry, f i s h , seafoods, and low-fat cheeses a re depended upon as the major sources for about 50;: of the protein each week.

The kind, t he cut, and the amount of meat allowed i n the diets These res t r ic t ions a r e necessary i n order

Dairy f a t s now provide 285

Obviously, if the t o t a l amount

The t o t a l f a t i n these special diets ranges from 30:: - 40$ -- qui te a reduction from the 42.5;: in the usual American diet ,

Rather s ignif icant chances have already occurred i n the d ie ta ry habits i n our country; more may be on the way. dis t r ibu te are d ras t i ca l ly cur ta i led in the special diets, I will give you some of the de ta i l s of t he diets designed t o reduce cholesterol. discuss the New York Prudent Diet, the American Heart Association d ie t , and the American Medical Association d ie t s . M x t of the diets i n use a re modi- f icat ions of the Prudent Diet, consideration of what is involved.

Because the products you

I Will

It, therefore, can be used as a basis f o r

The so-called prudent d i e t of t he "anti-coronary club" i s the one used i n a study conducted by the New York City Department of Health. Actually, two diets a re involved, one f o r weight reduction and one f o r weight maintenance. I w i l l discuss. calories as f a t . The 66 grams of f a t per day are, in part, composed of 1 9 grams of saturated f a t and 20 grams of polyunsaturated fat . The P/S r a t i o i s 1-05. The sources of protein permitted in the diet include cottage-type cheese, f a t - f r ee m i l k , chicken, turkey, veal, leaner cuts of beef, nutton, lamb, lean portions of pork, f ish, seafood, and eGg white. Meat must be baked, broiled, o r boiled, and special a t tent ion must be given t o remove a l l v i s ib l e fa t . Beef, lamb, mutton, and veal when used must be medium t o well done. The Eize of the serving depends upon the t o t a l mount of calor ies permitted.

The l a t t e r is called the prudent diet; it is the one The 2,000 calor ie maintenance diet provides 30% of the

In the prudent d ie t , of the 21 meals each week, beef, lamb, Veal o r fowl mutton, o r pork may be used not more often than four times.

may be used four times, f i sh o r seafood five times, and cottage-type cheese o r egg whites the remaining eight meals of the week, eaten each week. the special high l i no le i c acid margarines a re p e d t t e d . given detai led instructions on food selection and preparation and qui te a list of foods that a re not permitted. b s t of your products %re found in the forbidden list.

Four eggs may be One ounce of corn oil is t o be used each day, and only

Participants a re

The American Heart Association has released a booklet intended t o be used f o r patfent instruct ion in planning fat-controlled meals. following is an excerpt from the introduction:

The

"This booklet contains a d i e t that your doctor has prescribed f o r you. It is called a fat-controlled diet , because both the amount and the type of fat are carefully regulated .''

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"Your new diet w i l l d i f f e r from th is 'average' diet i n two ways: less fat--about 35 per cent of the day's calories, instead of 40 t o 45 per cent, and 2) of the f a t you eat , more wi31 come fromvegetable o i l s and less w f l l come f r o m meat and dairy products."

1) You w i l l have somewhat

"The purpose of this diet i s t o reduce the amount of cholesterol and other fatty substances in the blood. or retard the condition cal led atherosclerosis .'I

It is hoped that this will help prevent

"Although there is no def in i te proof t h a t changing the f a t content of the diet will prevent athero- sclerosis , a number of studies have pointed i n t h i s direction. able, many physicians agree that the wise course f o r selected pat ients is a simple diet designed t o lower the amount of cholesterol and other f a t s i n the blood."

Until more infomation is avai l -

The booklet is available t o pat ients on a physician's prescription only.

In t h i s diet, as i n others, only Shim milk, non-fat dry m i l k

The section on meat, f ish, and poultry contains specif ic ins tmc-

powder, o r b u t t e m i l k made from skim milk is permitted.

t ions. Six ounces per day are permitted. of the 14 main meals each week may be chosen from:

In the 1800 calor ie diet, three

beef (eye of round, top and bottom round, lean ground

lamb (leg only)

mund, lean lzullp and tenderloin)

pork (lean only)

ham (lean and well trimmed)

F o r t h e other U. meals of the week, choices may be made from among skinless chicken and turkey, f ish, seafood, veal, o r meat substi tutes.

The booklet contains specif ic i n s t rud ions f o r the pat ient t o avoid "choice" o r "prime" beef, lamb, except leg, pork, except lean loin, bacon, s a l t pork, spareribs, franlrl'urters, sausage, cold cuts, canned meats o r organ meats.

i n these diets, three l eve l tablespoons of cer ta in fats a re included each day. Four eggs may be used each week and need not be subst i tuted f o r some of the meat.

I n order t o provide the increased amount of l i no le i c acid required

The d i e t emphasizes vegetables, f r u i t s , and cereals.

The Council on Foods and Nutrition has prepared a report f o r the physician on the regulation of d ie ta ry f a t , The report contains six chapters

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with the following t i t l e s : Lipids, Amount and Kind of Fat i n the American Diet, Regulation of Dietary Fat, bkthods f o r Reducing Fat Intake, and Methods f o r Substituting Poly- unsaturated f o r Saturated Fat i n the D i e t . which we will be concerned.

Chemistry of the Lipids, Physiology of the

It is the l a s t chapter with

The Council concluded i n the report that: "Indications f o r re- s t r i c t i n g the t o t a l fat content of the d i e t may include g a l l bladder disease, cer ta in types of malabsorption and hypertriglyceridemia, The in- dication f o r increasing the degree of polyunsaturation of the fa t is hypercholesterolemia. Both hypercholesterolemia and hypertriglyceridemia have been associated with atherosclerosis. between diet o r serum l i p i d concentrations and atherosclerosis has not been proved. In the l i g h t of present knowledge, it appears log ica l t o attempt t o reduce high concentrations of cholesterol and other serum l i p i d s as an experimental therapeutic procedure."

A d i rec t casual relationship

The d i e t s designed t o bring about a reduction in cholesterol are given f o r three calor ie levels . The 1800 and 2400 calor ie d i e t s are in- tended as weight maintenance. Both provide fa t i n an amount t o equal 35$ - 40$ of t o t a l calories. The 1800 calor ie diet c a l l s f o r 70 grams of f a t , of which 20 grams are saturated f a t t y acids and 26 grams a re l i no le i c acid. The L/S r a t i o is, therefore, 1.3 t o 1. The 2400 calor ie d i e t c a l l s f o r 116 grams of f a t , of which 30 grams a r e saturated f a t t y acids and 45 grams are l i no le i c acid. s imilar t o those proposed by the A.H.A. reported earlier and need not be reported i n de ta i l .

The L/S r a t i o is 1.5 to 1. The diets are essent ia l ly

The only r ea l difference between the diet plans of the A 3 . A . and the A.M,A. i s i n the calor ie l eve l chosen f o r the maintenance of weight i n men. It is simply a diet unrestr ic ted in calories. the t o t a l number of calor ies i n any event.

The A.M.A. d i e t is given a t 2400 calories, the A,H.A. a t 2800 calories. The physician would prescribe

Now, uith t h i s inf'olmation before us, w h a t does it mean t o you? F i r s t , you must bear i n mind that these d i e t s are experimental and a r e used by physicians in attempts t o remove a degree of r i s k from t h e i r pat ients . Certainly the I h t r i t i o n Committee of the A.H.A. and the Council on Foods and Nutrition do not propose that their diets be ueed by the general public. Quite the contrary; both reports make it c lea r t ha t the material is addressed t o the physician.

Next, the d i e t s c a l l f o r only very moderate amounts of the products you provide t o the market. other animal f a t as necessary t o assure an adequate protein intake i s per- mitted. In f ac t , it would be safe t o say t ha t meat i s permitted primarily t o avoid too d ras t i c a deviation from the usual way of eating,

No milk f a t is permitted and only as l i t t l e

It seems c l ea r t o ne that, i f the trend continues, we w i l l need t o know more about the f a t t y acid composition of animal f a t s and of their e f fec t on body chemistry. One important requirement of the meat industry may be t o l ea rn how t o produce high proteb-low f a t (or modified fat) meat that i s tender and acceptable, Only time and continued research will de- termine whether the general public w i l l have t o modify i t s dietary habits i f cardiovascular disease is t o be avoided.

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MR. DOTY: I am sure there may be some questions and discussion about t h i s later, but l e t us mve along t o the last paper of the session.

fn t rying t o get someone t o discuss t h i s matter of proteins, par- t i cu l a r ly meat proteins, in human nutri t ion, the cammittee could f ind no one who they considered as w e l l qual i f ied as one of i t s own members. All of you know Joe Ifastelic, and witbout f i r t h e r ado he will t a l k to us th i s morning on Yeat Proteins i n Human Nutrition.

MR. JOE ICASTELIC: ( I l l i no i s ) bIr. Chairman, and D e l , and Members of the Reciprocal Meat Conference, and Friends;

I would l i k e t o say that I am very happy t o be given the privilege t o appear before you today because I consider it an honor, and I hope tha t nly thoughts w i l l not disappoint you.