ARE ALL FATS BAD?
The chief concern when discussing dietary fats is their role in promoting coronary heart disease. Other concerns involve their role in obesity and cancer, in particular of the breast, colon, and prostate.
Despite research, the relationship between fat intake and these outcomes is not entirely clear. We know that some fats play a protective role. Therefore it’s the type of fat intake that matters. While in the past the recommendation was to restrict fat to fewer than 30% of your daily caloric intake, the current recommendation is that your diet should consist of anywhere between 25 and 35% fat.
WHAT ARE THE DIFFERENT TYPES OF FAT?
There are 3 types of fats. They are called saturated fats, trans fats, and unsaturated fats. Bad fats: Saturated and trans fats have been implicated in increasing a person’s risk of Diabetes, heart disease, and cancer of the breast, colon, and prostate.
Saturated fats are derived from animal products. They have an adverse effect on your total and bad cholesterol values. Studies reveal a direct relationship between LDL (bad) cholesterol and coronary heart disease events.
Trans fats occur naturally in food especially of animal origin, although most of its consumption is from industrial hydrogenation of polyunsaturated (good) fats. Industrial hydrogenation allows easier handling of food for cooking. It keeps our pastries firm and our margarine soft. Trans fats have adverse effects on our LDL (bad cholesterol) and HDL (good cholesterol).
Unsaturated fats are found in olive and canola oils and fish oils. They decrease LDL (bad) cholesterol and maintain or elevate HDL (good) cholesterol. They may play a key role in preventing atherosclerosis and decreasing insulin resistance.
IF WE ELIMINATE MEAT FROM OUR DIET THEN DOES IT FOLLOW THAT PURE VEGETARIAN DIETS OFFER HEALTH BENEFITS?
The answer is yes and no.
Vegetarian diets are associated with a decreased incidence of obesity, coronary heart disease, hypertension, and type II diabetes. However the long term effects on morbidity and mortality are difficult to separate from those of vegetarian lifestyles which tend to be associated with regular exercise, avoidance of tobacco and alcohol use.
Let’s take a closer look…
The types of vegetarian diets are varied and have important implications for growth and development.
Vegetarian diets carry an increased risk of deficiencies in iron, zinc, calcium, and vitamins D and B12.
Iron is needed for our body to produce red blood cells. Iron comes from meat and we call this heme iron. Iron also comes from plant foods and we call this non-heme iron. Heme-iron is more easily absorbed and therefore better utilized by our body whereas non-heme iron is not as easily absorbed. Phytates are substances found in legumes, nuts, seeds, whole grains and soy that reduce non-heme iron absorption. Similarly, tanins and polyphenols are substances found in tea and coffee that further reduces non-heme iron absorption.
Calcium is needed to maintain healthy bones and keep our heart pumping. Most of our calcium needs can be met consuming dairy products. Vegan diets do not contain dairy products and vegetables, fruits, and cereals contain less calcium. Therefore vegans should increase their intake of higher calcium vegetables and fruits such as kale, turnips, broccoli, and dried figs. Alternatively calcium fortified foods such as soy milk can be substituted.
Vitamin D is important for bone formation and more recent data shows that vitamin D offers heart protection. Its principle source is fortified milk and sunlight exposure. Adequate sunlight exposure requires 10 to 15 minutes on 2 days per week in fair skinned people and 30 minutes on 3 days of the week in darker skinned people.
B12 is important to maintain a healthy nervous system and produce red blood cells. Meat and dairy products provide the only natural dietary sources. Vegetarians should consume increased amount of b fortified products such as cereals and soy.
CAN WE CONSUME ADEQUATE AMOUNTS OF PROTEIN FROM VEGETARIAN DIETS?
An important difference between protein of plant and animal origin is the concentration of essential amino acids they contain. Animal foods contain high quality also known as complete protein necessary for growth and repair. High quality protein contains all 9 essential amino acids. Plant based protein is incomplete protein. It is deficient in 1 or more of the essential amino acids. An amino acid deficiency of one plant food can be overcome by combining it with a complementary plant food that provides the missing amino acid. An example is combining grains which are deficient in lysine and high in methionine with legumes which are deficient in methionine and high in lysine. This combination creates a high quality protein.
Soy bean based products are essentially equivalent to animal protein and is an important source of protein for vegetarians.
DO VEGETARIAN DIETS PROMOTE WEIGHT LOSS?
The prevalence of obesity in the United States has been rising for decades. Fat is calorically dense. Therefore it is more important than a carbohydrate or protein in promoting obesity. A vegetarian diet is lower in calories and the higher fiber content makes you feel fuller on fewer calories
but… food choices are important.
Instead of replacing high fat foods with naturally low fat foods with other health benefits i.e. fruits and vegetables, consumers have often increased consumption of low fat or fat free varieties of naturally high fat food, i.e. fat free snack foods, which contain increased amounts of refined carbohydrates. This contributes to low good cholesterol levels and possibly an increased incidence of obesity and type II Diabetes.