stance of negligible harm.) In rat stud- 
ies, the carcinogenicity of aflatoxin 
is decreased when the intake of protein 
is also decreased. The least carcino- 
genic effect of aflatoxin appears to 
occur when protein levels are at or 
slightly below the recommended di- 
etary allowance. As the level of dietary 
protein is increased above its require- 
ment, aflatoxin carcinogenicity is also 
increased, although beyond a certain 
level of dietary protein (about 20 per- 
cent of total diet by weight) there 
appears to be no further increase. Sim- 
ilar data have also been published in 
other studies concerning other carcino- 
gens. Once again, the carcinogenic re- 
sponse is most prominent at higher 
levels of protein intake, with the mini- 
mum effect occurring at protein levels 
near the requirement. In other words, 
there must be an adequate intake to 
meet the many needs of the body but 
not an excessive intake that may in- 
crease the risk of cancer. Incidentally, 
several human epidemiological studies 
show an extremely impressive positive 
correlation between dietary protein in- 
take and cancer of the breast, colon, 
prostate, and pancreas. 
Vitamin C (ascorbic acid) is a 
unique nutrient in that it is required 
only by primates (including humans), 
the guinea pig, and a few other, lesser- 
known species. The daily intake of 
ascorbic acid recommended for 
humans is 60 milligrams (recently in- 
creased from an RDA of 45 milli- 
grams). The arguments advanced by 
Linus Pauling that vitamin C prevents 
the common cold and, perhaps, cancer 
specify enormous intakes of 10,000 
milligrams per day or more. Since it 
is almost impossible to get more than 
1 ,000 to 1 ,500 milligrams per day with 
traditional foods — even those high in 
ascorbic acid — such megadose effects, 
if they exist, would have to be re- 
garded as pharmacological rather than 
nutritional. There is evidence in lab- 
oratory studies on rats that vitamin 
C inhibits gastric and intestinal cancer 
caused by nitrosamines (compounds 
derived from the nitrites and nitrates 
that are added to, as well as found 
naturally in, certain foods). But ade- 
quate protection should be afforded 
by restricting intake to modest — not 
megadose — levels. In fact, at very 
high, or megadose, levels, there is an 
indication that vitamin C can be mu- 
tagenic, which might even suggest a 
carcinogenic response. 
Another nutrient for which inap- 
propriately low or high levels of intake 
may increase the risk of cancer is se- 
lenium. Although the data on this sub- 
stance need considerably more con- 
firmation, the existing data indicate, 
once again, that whereas an adequate 
nutritional intake minimizes cancer 
risk, more is not necessarily better. 
What then is the most appropriate 
dietary pattern that might allow for 
simultaneous nutritional benefits? The 
above-mentioned examples indicate 
that a diet lower than the current 
American one in total fat, linoleic 
acid, and protein, but higher in vi- 
tamin C, fiber, and selenium would 
hypothetically yield the lowest cancer 
risk. Such a dietary balance can be 
achieved by an increase in the con- 
sumption of whole grain cereal prod- 
ucts, vegetables, and fruits, and a re- 
duction in meats and foods prepared 
in fat. With that regimen, dietary fiber 
and vitamin C would be increased, 
while protein and total fat would be 
decreased. In addition, if less oil were 
used in cooking, linoleic acid consump- 
tion would also be decreased. Sele- 
nium intake, however, would not nec- 
essarily be altered by such a dietary 
change. The amount of selenium in 
a diet is determined primarily by the 
geographical area from which the food 
in the diet comes because the amount 
of selenium available in a particular 
soil apears to establish the selenium 
content in the food it yields. Moreover, 
individual nutrients such as vitamin 
C, vitamin A, vitamin E, certain amino 
acids, and polyunsaturated fatty acids 
may affect the uptake of selenium 
from the intestinal tract into the blood- 
stream. 
In summary, although it may not 
be possible to establish the specific 
effect of the intake of every individual 
nutrient on the cancer process, the 
reorientation of diet suggested here 
should bring about the desired simul- 
taneous alteration of nutrients. More- 
over, such a dietary pattern coincides 
with that recommended for the pre- 
vention of cardiovascular disease. In- 
deed, the same goals should be at- 
tained by following the dietary guide- 
lines recently established in the United 
States by the Department of Agri- 
culture and the Department of Health 
and Human Services. 
T. Colin Campbell is professor of nu- 
tritional biochemistry in the Division 
of Nutritional Sciences at Cornell 
University in Ithaca, New York, and 
director of the division’s nutrition and 
cancer program. 
Full-Line 
Leica dealers: 
ARIZONA— Phoenix: Foto Forum. Guild Camera 
CALIFORNIA (Northern)— Berkeley: Berkeley Commercial 
Photo Larkspur Landing. The Camera Company 
Monterey: Ken s Cameras Palo Alto: Keeble & Shuchat 
San Francisco: Adolph Gasser Brooks Cameras, The Darkroom. 
Pacific Camera San Mateo: Brooks Cameras 
Santa Cruz: Camera Connection Stockton: Gluskm s Camera 
Corner Walnut Creek: Photo Center 
CALIFORNIA (Southern)— Beverly Hills: Beverly Hills Camera 
Costa Mesa: Cal's Cameras Goleta: Tony Rose uamera 
Hollywood: Bob Gamble s Photo Los Angeles: Bel Air Camera 
Frank s Highland Park Camera. Kimura Photomart, Olympic 
Camera Pasadena: Alvin s Photo. Lee-Mac Camera Exchange 
Redondo Beach : Riviera Camera Shop 
COLORADO— Aspen Walnut House Denver Gart Bros 
Sporting Goods Waxman Camera. Werner s Mile High Camera 
Grand Junction: Monument Photographic Corp 
CONNECTICUT— Hamden: Karber Photo Hartford: Camera Bar 
New Haven: Fair Haven/Fairgraphics 
DELAWARE— Wilmington: Lincoln Camera 
DISTRICT OF COLUMBIA— Washington: Penn Camera 
Exchange. Pro Photo 
FLORIDA— Casselberry: international Camera 
Coral Gables: Mileo Photo Supply Fort Lauderdale; Cltk Camera 
Shop Lake Worth: Quality Photo Service Miami: Benson s 
Camera. Bristol's. Downtown Camera, Miami Camera Center, 
Pitman Photo Palm Beach: Ramon s Camera Shop 
St Petersburg: Abner s Camera Exchange Tampa: Southern 
Photo & News 
GEORGIA— Atlanta: Crown Camera Exchange. 
Wallis Kamera Haus 
HAWAII— Honolulu: Francis Camera Shop 
IDAHO— Boise: Idaho Camera 
ILLINOIS— Chicago: Camera Exchange Central Camera. Helix 
Ltd Herman Cameras. Shutan Camera Evanston: Poes 
Camera Orland Park: Camera Cove Peoria: Peoria Camera 
INDIANA— Muncie: Jack s Camera South Bend: Schilling s 
IOWA— Iowa City: Henry Louis 
KANSAS— Kansas City: Western Photo-Graphic 
Topeka: Wolfe's Camera Shop Wichita: Lawrence Photo 
LOUISIANA— New Orleans: Alfredo s Cameras 
Shreveport: Par Excellence 
MARYLAND— Rockville: Bunton Instrument 
Silver Spring: Industrial Photo Wheaton: Gilbert's 
MASSACHUSETTS— Arlington: New England Photo 
Boston: Claus Gelotte E Philip Levine Cambridge: Claus 
Gelotte Chicopee: Piepul s Camera Malden: Hunt Drug 
MICHIGAN— Ann Arbor: Home Appliance Mart 
Birmingham: Birmingham Camera World Camera 
Dearborn: Adray Appliance Muskegon: Al Christopher s Camera 
Royal Oak: Century Camera 
MINNESOTA- Golden Valley: National Camera 
Minneapolis Photo Visuals 
MISSOURI— Kansas City: Crick s Camera St. Louis: Creve 
Coeur Camera St Louis Photo Springfield: Ozark Camera 
NEBRASKA— Omaha; Dean s Camera 
NEW HAMPSHIRE— Hanover: Camera Shop of Hanover 
Manchester: The Camera Shop 
NEW JERSEY- Bricktown. The Photo Center Northfield: Corral 
Camera Lounge Parsippany: Sight and Sound 
Upper Montclair: Photo Cullen 
NEW YORK- Albany: State Photo Supply Amityville: Berger 
Bros Camera Bronx: Arista Camera Specialists 
Brooklyn: Focus Electronics Buffalo: Delaware Camera Mart 
Great Neck: Ken-Mar Camera New York City: Alkit Camera 
Shoppe Cambridge Camera Exchange. Camera Barn, Competitive 
Camera. Dumont Camera Executive Photo & Supply, 
47th Street Photo. Jaydee Camera Exchange. Ken Hansen Photo 
Olden Camera & Lens. Wall Street Camera Exchange: 
Willoughby s Newburgh: Seaman s Rochester: Photogenesis 
Camera Center Schenectady: Reales Syracuse: M Q Camera 
Center Yonkers: Sam's Camera Exchange 
NORTH CAROLINA— Greensboro: Camera World 
Raleigh: Sam Bass Camera Shop 
OHIO— Akron: Metzger Photo Supply Bedford Heights: Laurel 
Camera Cincinnati: Growth Systems. Provident Camera 
Cleveland: The Dodd Company Dayton: Malone Camera 
Worthington: Don McAlister Camera 
OKLAHOMA— Oklahoma City: Pipkin Photo Supply 
Tjlsa: Camera Gallery, Engler Photo Supply 
OREGON— Beaverton: Suburban Photo Corvallis: Oregon State 
University Book Store Portland: Citizens Photo. Conklmg. Inc 
PENNSYLVANIA— Allentown: Classic Photo Lab Ephrata: Lees 
Camera Center Philadelphia: Kosmm's Camera Exchange. 
Photo-Cine Shop Pittsburgh: Kadet Photo Reading: Alton E 
Bower's Photo 
RHODE ISLAND— Providence: Adlers 
TENNESSEE— Memphis: Memphis Photo Supply 
Nashville: McGinnis. Inc Photographic Systems 
TEXAS— Austin: Capitol Camera Dallas: Cooter s Village 
Camera Fort Worth: Seymour s Photo Supply Houston: George 
Lange/Cameras. Southwestern Camera New Braunfels: Seidel 
Camera Shop Tomball: Custom Camera 
VERMONT— Burlington: Photogarden 
VIRGINIA— Charlottesville: Cary's Camera Shop Fairfax: Fuller 
and D Albert Williamsburg: Massey s Camera Shop 
WASHINGTON- Seattle: Clyed's Camera Stores. Olympic Camera 
Center. University Book Store Spokane: Huppms Hi Fi & Photo 
WISCONSIN— Appleton: Ideal Photo Milwaukee: Casanova s. 
Reimer s Photo Materials Racine: Camera World 
Or write for more information. 
E. Leitz, Inc., Rockleigh, N.J. 07647. 
16 
