Can Going on Vegetarian Diet make You Lose Weight ?

vegan diet foods
vegetarian diet

Vegetarian Diet

More and more people are choosing to follow a vegetarian diet for many different reasons. It’s estimated that two per cent of the population now don’t eat meat or fish.

Reasons for switching to a vegetarian diet include:

  • the health benefits
  • ethical and moral reasons
  • religious or cultural reasons
  • concern for animal welfare
  • concern about the environment and sustainability
  • taste – some people just don’t like the taste of meat or fish.

A vegetarian diet, based on unprocessed foods, can provide many health benefits. Vegetarian diets can be healthful and nutritionally sound if they’re carefully planned to include essential nutrients. However, a vegetarian diet can be unhealthy if it contains too many calories and/or saturated fat and not enough important nutrients.

Research has shown that the foods you eat influence your health. Eating certain foods, such as fruits and nuts, has been associated with reduced death rates, while other foods, such as red meat and processed meat, have been linked to increased mortality. Studies comparing overall eating patterns and mortality rates, however, have had mixed results.

For advice and help with what to eat and including vegetarian recipes go to the Vegetarian Society 2).

What is a vegetarian ?

According to the Vegetarian Society 3), a vegetarian is:

  • “Someone who lives on a diet of grains, pulses, legumes, nuts, seeds, vegetables, fruits, fungi, algae, yeast and/or some other non-animal-based foods (e.g. salt) with, or without, dairy products, honey and/or eggs. A vegetarian does not eat foods that consist of, or have been produced with the aid of products consisting of or created from, any part of the body of a living or dead animal. This includes meat, poultry, fish, shellfish*, insects, by-products of slaughter** or any food made with processing aids created from these.”
  • * Shellfish are typically ‘a sea animal covered with a shell’. We take shellfish to mean; Crustaceans (hard external shell) e.g. lobsters, crayfish, crabs, prawns, shrimps; Molluscs (most are protected by a shell) e.g. mussels, oysters, winkles, limpets, clams, etc. Also includes cephalopods such as cuttlefish, squid, octopus.
  • ** By-products of slaughter includes gelatine, isinglass and animal rennet.
  • Eggs: Many lacto-ovo vegetarians will only eat free-range eggs. This is because of welfare objections to the intensive farming of hens. Through its Vegetarian Society Approved trademark scheme, the Vegetarian Society will only license its trademark to products containing free-range eggs where eggs are used.

There are different types of vegetarians:

  • Lacto-ovo-vegetarians eat both dairy products and eggs (usually free range). This is the most common type of vegetarian diet 4).
  • Lacto-vegetarians eat dairy products, but avoid eggs.
  • Ovo-vegetarian. Eats eggs but not dairy products.
  • Vegans do not any products derived from animals – no meat, fish, dairy or eggs.

For advice and help with what to eat and including vegetarian recipes go to the Vegetarian Society 5).

In general, vegetarians had significantly lower intakes of protein, saturated fat and cholesterol and significantly higher intakes of dietary fiber and vitamin C than omnivorous diets 6).

Vegetarian Diet and Weight Loss

Strict vegetarians is a diet based on plants who enjoy a variety of delicious foods — just not meat, fish, or fowl ! Examples include whole grain breads, enriched cereals, nuts, peanut butter, eggs, legumes and soy products, tofu, vegetables and fruits, pasta and rice, and low-fat dairy products. Vegetarian diets vary, depending on how many foods of animal origin are included.

Here are some of the popular types:

  • Quasi-vegetarian. The diet includes fish and poultry but not red meat.
  • Pescatarian. The diet includes plants and fish.
  • Semi-vegetarian. Meat occasionally is included in the diet. Some semi-vegetarians may not eat red meat but may eat fish and perhaps chicken.
  • Lacto-ovovegetarian (lacto – dairy; ovo – eggs). The diet includes eggs, milk, and milk products but no meat or fish is consumed.
  • Lactovegetarian. Milk and milk products are included in the diet, but not eggs or meat or fish.
  • Vegan. The diet excludes all fish and animal products, including eggs, milk, and milk products.

In one study, researchers found that while obesity is growing in the United States, it only affects 0% to 6% of vegetarians. Other studies show that vegetarian children tend to be leaner than children who eat animal foods.

The vegetarian’s lower average body weight may be linked to the high fiber content of plant foods. Plant fiber fills you up quickly, and can result in less snacking and binging later in the day.

In a large European study measuring the body mass index (BMI) of 37,875 healthy men and women aged 20-97 years with four different diet types (meat-eaters, fish-eaters, vegetarians and vegans) found that fish-eaters, vegetarians and especially vegans had lower BMI than meat-eaters 7). The age-adjusted mean body mass index (BMI) was significantly different between the four diet groups, being highest in the meat-eaters (24.41 kg/m(2) in men, 23.52 kg/m(2) in women) and lowest in the vegans (22.49 kg/m(2) in men, 21.98 kg/m(2) in women). Fish-eaters and vegetarians had similar, intermediate mean BMI. Differences in lifestyle factors including smoking, physical activity and education level accounted for less than 5% of the difference in mean age-adjusted BMI between meat-eaters and vegans, whereas differences in macronutrient intake accounted for about half of the difference. The study also found that high protein (as percent energy) and low fibre intakes were the dietary factors most strongly and consistently associated with increasing BMI both between and within the diet groups 8).

  • Is it true that switching to a vegetarian diet will automatically result in weight loss ?

Not necessarily. A vegetarian diet is not inherently a weight-loss diet, but rather a lifestyle choice. However, on the whole, vegetarian diets tend to be lower in calories and higher in fiber, making you feel full on fewer calories. They can definitely help you shed unwanted pounds when done correctly. Adults and children who follow a vegetarian diet are generally leaner than those who follow a non-vegetarian diet. This may be because a vegetarian diet typically emphasizes more fruits and vegetables and includes whole grains and plant-based proteins — foods that are more filling, less calorie dense and lower in fat.

But a vegetarian diet isn’t automatically low calorie. You can also gain weight on a vegetarian diet if your portion sizes are too big or if you eat too many high-calorie foods, such as sweetened beverages, fried items, snack foods and desserts. For example, if you cut out meat but replace it with lots of cheese and nuts, you could end up consuming the same number of calories (or even more).

You do get larger portions of vegetarian foods, because many are lower in calories than animal foods like hamburgers, ham, and pork. But you still have to eat fewer calories than you burn each day to lose weight.

Even some foods marketed as vegetarian can be high in calories and fat, such as soy hot dogs, soy cheese, fried beans and snack bars.

No matter what the some might claim, calories count. You cannot eat unlimited pasta with cheese, ice cream, and mashed potatoes (all vegetarian dishes) without gaining weight.

According to the Academy of Nutrition and Dietetics, an evidence-based review showed that a vegetarian diet is associated with a lower risk of death from ischemic heart disease. Vegetarians appear to have lower low-density lipoprotein cholesterol levels, lower blood pressure and lower rates of hypertension and type 2 diabetes than meat eaters. Vegetarians also tend to have a lower body mass index, lower overall cancer rates and lower risk of chronic disease.

Lastly, sometimes people call themselves “vegetarians,” but eat an unbalanced diet of peanut butter and jelly sandwiches and French fries, leaving their bodies nutritionally deprived.

The most important thing for vegetarians of all kinds to remember is to make sure they are getting key nutrients, including protein, fatty acids, iron, zinc, iodine, calcium, selenium and vitamins D, riboflavin (vitamin B2) and vitamin B-12. Protein is essential for building muscle mass, amino function, fighting disease and healing.

Taking a daily vitamin mineral supplement that provides complete amounts of the above nutrients is another way to ensure adequate nutrition. And getting plenty of sunshine is one way to satisfy the body’s requirement for vitamin D.

If you adopt a vegan diet, you also need to understand the concept of complementary proteins. Animal protein is complete, meaning it contains all the amino acids essential to a healthy diet. Plant foods contain plenty of protein, but their amino acids are incomplete. So to make sure you’re getting complete protein, eat different plant foods in combination — for example, by having beans along with your rice. Vegans need to pay close attention to their diets to make sure they are nutritionally adequate.

There are numerous research-proven health benefits to following a vegetarian diet, but only if you’re doing it properly and not substituting meat with processed or high-fat vegetarian products. Just make sure you learn more about your special nutritional requirements before you add or exclude any food or groups of foods.

Whether you avoid or eat meat or animal products, the basics of achieving and maintaining a healthy weight are the same for all people. Eat a healthy diet and balance calories eaten with calories burned.

Vegetarian diet nutrients to consider 9)

Below are the key nutrients to consider with a vegetarian diet.

  • Protein: You don’t need to eat foods from animals to have enough protein in your diet. Plant proteins alone can provide enough of the essential and non-essential amino acids, as long as sources of dietary protein are varied and caloric intake is high enough to meet energy needs.
  • Whole grains, legumes, vegetables, seeds and nuts all contain both essential and non-essential amino acids. You don’t need to consciously combine these foods (“complementary proteins”) within a given meal.
  • Soy protein has been shown to be equal to proteins of animal origin. It can be your sole protein source if you choose.
  • Iron: Vegetarians may have a greater risk of iron deficiency than nonvegetarians. The richest sources of iron are red meat, liver and egg yolk — all high in cholesterol. However, dried beans, spinach, enriched products, brewer’s yeast and dried fruits are all good plant sources of iron.
  • Vitamin B-12: This comes naturally only from animal sources. Vegans need a reliable source of vitamin B-12. It can be found in some fortified (not enriched) breakfast cereals, fortified soy beverages, some brands of nutritional (brewer’s) yeast and other foods (check the labels), as well as vitamin supplements.
  • Vitamin D: Vegans should have a reliable source of vitamin D. Vegans who don’t get much sunlight may need a supplement.
  • Calcium: Studies show that vegetarians absorb and retain more calcium from foods than nonvegetarians do. Vegetable greens such as spinach, kale and broccoli, and some legumes and soybean products, are good sources of calcium from plants.
  • Zinc: Zinc is needed for growth and development. Good plant sources include grains, nuts and legumes. Shellfish are an excellent source of zinc. Take care to select supplements containing no more than 15-18 mg zinc. Supplements containing 50 mg or more may lower HDL (“good”) cholesterol in some people.

Vegetables are categorized into five subgroups 10):

  1. dark-green,
  2. red and orange,
  3. beans and peas (legumes),
  4. starchy,
  5. and other vegetables. Cruciferous vegetables fall into the “dark-green vegetables” category and the “other vegetables” category.

The amount of vegetables you need to eat depends on your age, sex, and level of physical activity. Recommended total daily amounts and recommended weekly amounts from each vegetable subgroup are shown in the two tables below.

Table 1: Daily Vegetables Recommendation 11)
Children2-3 years old

4-8 years old

1 cup

1 ½ cups

Girls9-13 years old

14-18 years old

2 cups

2 ½ cups

Boys9-13 years old

14-18 years old

2 ½ cups

3 cups

Women19-30 years old

31-50 years old

51+ years old

2 ½ cups

2 ½ cups

2 cups

Men19-30 years old

31-50 years old

51+ years old

3 cups

3 cups

2 ½ cups

Note: These amounts are appropriate for individuals who get less than 30 minutes per day of moderate physical activity, beyond normal daily activities. Those who are more physically active may be able to consume more while staying within calorie needs.
Table 2: Weekly Vegetables Recommendation 12)
Dark green vegetablesRed and orange vegetablesBeans and peasStarchy vegetablesOther vegetables
Amount per Week
Children 

2-3 yrs old

4-8 yrs old

 

½ cup

1 cup

 

2 ½ cups

3 cups

 

½ cup

½ cup

 

2 cups

3 ½ cups

 

1 ½ cups

2 ½ cups

Girls

9-13 yrs old

14-18 yrs old

 

1 ½ cups

1 ½ cups

 

4 cups

5 ½ cups

 

1 cup

1 ½ cups

 

4 cups

5 cups

 

3 ½ cups

4 cups

Boys

9-13 yrs old

14-18 yrs old

 

1 ½ cups

2 cups

 

5 ½ cups

6 cups

 

1 ½ cups

2 cups

 

5 cups

6 cups

 

4 cups

5 cups

Women

19-30 yrs old

31-50 yrs old

51+ yrs old

 

1 ½ cups

1 ½ cups

1 ½ cups

 

5 ½ cups

5 ½ cups

4 cups

 

1 ½ cups

1 ½ cups

1 cup

 

5 cups

5 cups

4 cups

 

4 cups

4 cups

3 ½ cups

Men

19-30 yrs old

31-50 yrs old

51+ yrs old

 

2 cups

2 cups

1 ½ cups

 

6 cups

6 cups

5 ½ cups

 

2 cups

2 cups

1 ½ cups

 

6 cups

6 cups

5 cups

 

5 cups

5 cups

4 cups

Note: Vegetable subgroup recommendations are given as amounts to eat WEEKLY. It is not necessary to eat vegetables from each subgroup daily. However, over a week, try to consume the amounts listed from each subgroup as a way to reach your daily intake recommendation.

1 Cup of Vegetable: In general, 1 cup of raw or cooked vegetables or vegetable juice, or 2 cups of raw leafy greens can be considered as 1 cup from the Vegetable Group.

More information about vegetables and diet, including how much of these foods should be eaten daily or weekly, is available from the U.S. Department of Agriculture website Choose My Plate 13).

Vegetarian Diet Potential Health Benefits

Vegetarian diets can be healthful and nutritionally sound if they’re carefully planned to include essential nutrients. Specifically, Johnson lays out several potential benefits of a vegetarian diet:

  • Healthier weight. Vegetarians may be more likely to be at a healthy weight compared to meat eaters.
  • Lower incidence of heart disease. Vegetarians seem to have a lower incidence of heart disease than meat eaters. The unsaturated fats found in soybeans, seeds, avocados, nuts, olives and other foods of plant origin tend to reduce the risk of heart disease. Plant-based diets tend to be higher in fiber and are associated with healthy blood lipids.
  • Lower blood pressure and less hypertension. Vegetarians tend to have lower blood pressure and lower rates of hypertension than nonvegetarians. This may be related to vegetarians being at a healthy body weight, which helps maintain a healthy blood pressure.

Vegetarian Diet Potential Risks

  • Lack of nutrients. There can be risks linked to vegetarian diets associated with a lack of nutrients. If you are not careful to get the nutrients you need, you could experience a lack of protein, iron, zinc, calcium, vitamin B12, vitamin D and omega-3 fatty acids.
  • Unhealthy if contains too many calories. It is important to note a vegetarian diet can be unhealthy if it contains too many calories and/or saturated fat and not enough important nutrients.

It would be helpful for you following a vegetarian diet to see a registered dietitian to assure that all your nutrient needs are being met.

 

vegan diet foods

If I switch to a vegan diet, will I lose weight ?

What is Vegan Diet ?

A vegan diet is a total vegetarian diet. Besides not eating meat, vegans don’t eat food that comes from animals in any way. That includes milk (dairy) products, eggs, fish, honey, and gelatin (which comes from bones and other animal tissue).

In a small Swedish study involving 30 teenagers (average age 17.5 years) who are eating the vegan diet 14). The study found that the dietary habits of the vegans varied considerably and did not comply with the average requirements for some essential nutrients. Vegans had dietary intakes lower than the average requirements of riboflavin (vitamin B2), vitamin B-12, vitamin D, calcium, and selenium. Intakes of calcium and selenium remained low even with the inclusion of dietary supplements 15). This study result is consistent with another study showing the health effects of vegan diets 16).

Will you lose weight on a vegan diet ?

A vegan diet is not inherently a weight-loss diet, but rather a lifestyle choice.

It is true, that adults and children who follow a vegan diet are generally leaner than those who follow a non-vegan diet. This may be because a vegan diet typically emphasizes more fruits and vegetables and includes whole grains and plant-based proteins — foods that are more filling, less calorie dense and lower in fat. Vegan diets can contain a lot of fiber. Fiber is great because it fills you up without adding a lot of calories.

A study looking at the health effects of people on the vegetarian diets and vegan diets 17) found that vegan diets when compared to vegetarian diets vegan diets tend to contain less saturated fat and cholesterol and more dietary fiber. Vegans tend to be thinner, have lower serum cholesterol, and lower blood pressure, reducing their risk of heart disease. However, eliminating all animal products from the diet increases the risk of certain nutritional deficiencies. Micronutrients of special concern for the vegan include vitamins B-12 and D, calcium, and long-chain n-3 (omega-3) fatty acids. Unless vegans regularly consume foods that are fortified with these nutrients, appropriate supplements should be consumed. In some cases, iron and zinc status of vegans may also be of concern because of the limited bioavailability of these minerals 18). On the other hand, vegetarian diets contain higher content for vitamins A, C, and E, thiamin, riboflavin, folate, calcium, magnesium, and iron, suggesting that vegetarian diets are nutrient dense, consistent with dietary guidelines, and could be recommended for weight management without compromising diet quality 19).

The study of Appleby and colleagues 20) with 34,696 participants (7947 men and 26,749 women aged 20-89 years, including 19,249 meat eaters, 4901 fish eaters, 9420 vegetarians and 1126 vegans) points to the increased fracture risk in vegans compared to omnivorous, pesco-vegetarians and vegetarians. The higher fracture risk in the vegans appeared to be a consequence of their considerably lower mean calcium intake. An adequate calcium intake is essential for bone health, irrespective of dietary preferences 21).

So going back to the question whether you will lose weight by going on a vegan diet, the answer is not necessarily true that you will lose weight. Because a vegan diet isn’t automatically low calorie diet. You can gain weight even on a vegan diet if your portion sizes are too big or if you eat too many high-calorie foods, such as sweetened beverages, fried items, snack foods and desserts.

Even some foods marketed as vegan can be high in calories, salt, sugar and fat, such as soy hot dogs, fried beans and snack bars.

Whether you avoid or eat meat or animal products, the basics of achieving and maintaining a healthy weight are the same for all people. Eat a healthy diet and balance calories eaten with calories burned.

If properly planned, a vegan diet can provide all the nutrients you need. In general, people who don’t eat meat:

  • Weigh less than people who eat meat.
  • Are less likely to die of heart disease.
  • Have lower cholesterol levels.
  • Are less likely to get: High blood pressure, prostate cancer, colon cancer and type 2 diabetes.

There are many reasons why some people choose a vegan diet:

  • It can be healthier than other diets.
  • Some people think it’s wrong to use animals for food.
  • Some religions forbid eating meat.
  • A vegan diet can cost less than a diet that includes meat.
  • Eating less meat can be better for the environment, because most meat is commercially farmed.
  • Some people don’t like the taste of meat.

While there is no research on vegan diet and mortality, there are research that gives support that those on a vegetarian diet tended to have a lower rate of death due to cardiovascular disease, diabetes, and renal disorders such as kidney failure. And there was no association was detected in this study between diet and deaths due to cancer. The researchers also found that the beneficial associations between a vegetarian diet and mortality tended to be stronger in men than in women.

Good health could be related to a diet of mostly fruits, vegetables, and whole grains.

How can vegans eat a balanced diet ?

You may be worried that you won’t get all the nutrients you need with a vegan diet. But as long as you eat a variety of foods, there are only a few things you need to pay special attention to.

  • Calcium for people who don’t eat milk products. If you don’t get your calcium from milk products, you need to eat a lot of other calcium-rich foods. Calcium-fortified breakfast cereals, soy milk, and orange juice are good choices. Calcium-fortified means that the manufacturer has added calcium to the food. Other foods that have calcium include certain legumes, certain leafy green vegetables, nuts, seeds, and tofu. If you don’t use calcium-fortified foods, ask your doctor if you should take a daily calcium supplement.
  • Vitamin D for people who don’t eat milk products. Getting enough calcium and vitamin D is important to keep bones strong. People who don’t eat milk products can use fortified soy milk and breakfast cereals.
  • Iron. Getting enough iron is not a problem for vegans who take care to eat a wide variety of food. Our bodies don’t absorb iron from plant foods as well as they absorb iron from meats. So it’s important for vegans to regularly eat iron-rich foods. Vegan iron sources include cooked dried beans, peas, and lentils; leafy green vegetables; and iron-fortified grain products. And eating foods rich in vitamin C will help your body absorb iron.
  • Vitamin B12. Vitamin B12 comes from animal sources only. If you are a vegan, you’ll need to rely on food that is fortified with this vitamin (for example, soy milk and breakfast cereals) or take supplements. This is especially important for vegan women who are pregnant or breastfeeding.

Vegans also need to make sure they get the following nutrients:

  • Protein. When considering a vegan diet, many people worry that they will not get enough protein. But eating a wide variety of protein-rich foods such as soy products, legumes, lentils, grains, nuts, whole grains and seeds will give you the protein you need.
  • Omega-3 fatty acids. Without fish and eggs in your diet, you need to find other good sources of omega-3 fatty acids, such as hemp seeds, flaxseeds, pumpkin seeds, walnuts, certain leafy green vegetables, soybean oil, canola oil, and sea vegetables (such as arame, dulse, nori, kelp, kombu or wakame).
  • Zinc. Your body absorbs zinc better when it comes from meat than when it comes from plants. But vegans don’t usually have a problem getting enough zinc if they eat lots of other foods that are good sources of zinc, including whole-grain breads, cooked dried beans and lentils, soy foods, and vegetables.
  • Iodine. Iodine is a component in thyroid hormones, which help regulate metabolism, growth and function of key organs. Vegans may not get enough iodine and may be at risk of deficiency and possibly even a goiter. In addition, foods such as soybeans, cruciferous vegetables and sweet potatoes may promote a goiter. However, just 1/4 teaspoon of iodized salt a day provides a significant amount of iodine.

If you’re contemplating to give vegan diet a go, talk to a registered dietitian or nutrionist to learn how to plan a healthy vegan diet. A vegan diet excludes all animal products, including dairy. So it’s easy to miss certain key nutrients that are crucial to health. Protein, calcium, vitamins D and B12, omega-3 fatty acids, iron, zinc, and Iodine — they are all harder to get when you are vegan.

In most cases, you can get them from plants. But you may need to take a daily supplement for some nutrients like B12 or calcium because it’s hard to get enough from plant sources. And certain nutrients, like iron and zinc, are harder to absorb from plant-based foods. Good news is, a lot of foods, like cereal, are fortified to include these nutrients, which can make it easier to get them into your meal plan.

Comparison of Nutritional Quality of the Vegan, Vegetarian, Semi-Vegetarian, Pesco-Vegetarian and Omnivorous Diet

A study was performed to analyze and compare the nutrient intake and the diet quality of vegans, vegetarians, semi-vegetarians, pesco-vegetarians and omnivorous subjects (total 1475 participants) 22). Three out of four were females and almost 50% were less than 30 years of age. Hundred and four persons were following a vegan diet (7.1%), 573 (38.8%) were vegetarians, 498 (33.8%) declared to be semi-vegetarians, 145 (9.8%) were pesco-vegetarians and 155 (10.5%) were omnivores. The percentages of participants with normal weights varied from 78.8% for vegans to 67.7% for omnivores; 8.7% of vegans were underweight, which was comparable with vegetarians and pesco-vegetarians. The prevalence of overweight and obesity was the highest for the omnivores, respectively 20.6% and 8.4%, and lowest for vegans (respectively 10.6% and 1.9%). Almost 80% of the sample had a university or university college level of education.

Except for the omnivores, all diet groups had a comparable number of underweight subjects (ranging from 6.2% to 8.9%), whilst this was only 3.2% for the omnivores. These percentages were reversed for overweight and obesity, with a higher prevalence of overweight and obese subjects amongst the omnivores compared to the other diet groups. These findings are in agreement with published literature, where pesco-vegetarians, vegetarians and especially vegans had lower BMI than meat-eaters 23).

Nutritional intake of vegans compared to an omnivorous diet is in line with earlier research on vegans. Indeed, the most restricted diet had lowest total energy intake, better fat intake profile (i.e., lower cholesterol, total and saturated fat and higher poly-unsaturated fat), lowest protein and highest dietary fiber intake in contrast to the omnivorous diet 24). The intakes of the prudent diets were in between the vegan and omnivorous values. Absolute carbohydrate and sugar intakes were of the same magnitude across all diets, whilst relative intakes were highest in the vegan and lowest in the omnivorous diet. The higher carbohydrate intake as a function of the restriction results in a better macronutrient distribution for the more restrictive diets, which is in line with the literature 25).

It is well known that fruit is an important contributor of carbohydrates and sugars, especially in the more restricted diets, where fruit consumption is generally high 26). Moreover, other common and less healthy sources of sugar (i.e., candy, chocolate, cake and cookies) often contain animal products allowing only limited availability of these sugar sources for vegans 27). Sodium intake in vegans is less than half of the omnivorous intake. Although not of the same magnitude, lower sodium intakes have been reported when comparing respectively vegetarian 28) and vegan diets 29) with omnivorous diets. The restrictive diets allowing dairy consumption had the highest calcium intakes with the vegans only reaching half of these values. Indeed, in Western countries, dairy products are a major source of calcium in most diets 30). The study of Appleby and colleagues 31) points to the increased fracture risk in vegans compared to omnivorous, pesco-vegetarians and vegetarians. The higher fracture risk in the vegans appeared to be a consequence of their considerably lower mean calcium intake. An adequate calcium intake is essential for bone health, irrespective of dietary preferences 32). In agreement with the EPIC-Oxford study, a certain similarity was detected for the calcium intakes for omnivores, vegetarians, semi-vegetarians and pesco-vegetarians 33). The iron intake, with the most favorable values for the vegans, will not automatically result in an optimal iron status, since absorption of non-haem iron is less efficient 34), 35). Analysis of the different components of the Healthy Eating Index 2010 and the Mediterranean Diet Score indicate that vegans obtained the better scores for vegetables and legumes. The study of Ball & Bartlett demonstrated the importance of the vegetables component when comparing the iron intake of vegetarian versus omnivorous women 36). The results are in line with those of the comparative study of Larsson & Johansson on vegan adolescents versus omnivores where vegan iron intake in females was significantly higher compared to their omnivorous counterparts 37). The uneven gender distribution in this study vegan sample (70% females) may partly explain these high iron intakes since dietary practices in women are generally better than those in men 38).

Vegetarian Diets Linked to Lower Mortality

Adults who eat a more plant-based diet may be boosting their chance of living longer, according to a large analysis.

Researchers studied more than 73,000 Seventh-day Adventist men and women ages 25 and older 39). The participants were categorized into dietary groups at the time of recruitment based on their reported food intake during the previous year. Nearly half of the participants were nonvegetarian, eating red meat, poultry, fish, milk and eggs more than once a week. Of the remaining, 8% were vegan (eating red meat, fish, poultry, dairy or eggs less than once a month); 29% were lacto-ovo vegetarians (eating eggs and/or dairy products, but red meat, fish or poultry less than once per month); 10% were pesco-vegetarians (eating fish, milk and eggs but rarely red meat or poultry); and 5% were semi-vegetarian (eating red meat, poultry and fish less than once per week).

Over about 6 years, there were 2,570 deaths among the participants. The researchers found that vegetarians (those with vegan, and lacto-ovo-, pesco-, and semi-vegetarian diets) were 12% less likely to die from all causes combined compared to nonvegetarians. The death rates for subgroups of vegans, lacto-ovo–vegetarians, and pesco-vegetarians were all significantly lower than those of nonvegetarians.

Those on a vegetarian diet tended to have a lower rate of death due to cardiovascular disease, diabetes, and renal disorders such as kidney failure. No association was detected in this study between diet and deaths due to cancer. The researchers also found that the beneficial associations between a vegetarian diet and mortality tended to be stronger in men than in women.

The researchers note several limitations to the study. Participants only reported their diet at the beginning of the study, and their eating patterns might have changed over time. In addition, they were only followed for an average of 6 years; it may take longer for dietary patterns to influence mortality 40).

Vegetarian Diet and Mortality from Cardiovascular Disease

A study involving 11,000 vegetarians and health conscious people over 17 years 41), the results were: 2064 (19%) subjects smoked, 4627 (43%) were vegetarian, 6699 (62%) ate wholemeal bread daily, 2948 (27%) ate bran cereals daily, 4091 (38%) ate nuts or dried fruit daily, 8304 (77%) ate fresh fruit daily, and 4105 (38%) ate raw salad daily. After a mean of 16.8 years follow up there were 1343 deaths before age 80. Overall the cohort had a mortality about half that of the general population. Within the cohort, daily consumption of fresh fruit was associated with significantly reduced mortality from ischaemic heart disease (heart attack), cerebrovascular disease (stroke), and for all causes combined. The conclusion from that study 42): in health conscious individuals, daily consumption of fresh fruit is associated with a reduced mortality from ischaemic heart disease, cerebrovascular disease, and all causes combined.

Cruciferous Vegetables and Cancer Prevention

Cruciferous vegetables are part of the Brassica genus of plants 43). They include the following vegetables, among others:

  • Arugula
  • Bok choy
  • Broccoli
  • Brussels sprouts
  • Cabbage
  • Cauliflower
  • Collard greens
  • Horseradish
  • Kale
  • Radishes
  • Rutabaga
  • Turnips
  • Watercress
  • Wasabi

Researchers have investigated possible associations between intake of cruciferous vegetables and the risk of cancer. Studies in humans, however, have shown mixed results.

A few studies have shown that the bioactive components of cruciferous vegetables can have beneficial effects on biomarkers of cancer-related processes in people. For example, one study found that indole-3-carbinol was more effective than placebo in reducing the growth of abnormal cells on the surface of the cervix 44).

In addition, several case-control studies have shown that specific forms of the gene that encodes glutathione S-transferase, which is the enzyme that metabolizes and helps eliminate isothiocyanates from the body, may influence the association between cruciferous vegetable intake and human lung and colorectal cancer risk 45), 46), 47).

Higher consumption of vegetables in general may protect against some diseases, including some types of cancer. However, when researchers try to distinguish cruciferous vegetables from other foods in the diet, it can be challenging to get clear results because study participants may have trouble remembering precisely what they ate. Also, people who eat cruciferous vegetables may be more likely than people who don’t to have other healthy behaviors that reduce disease risk. It is also possible that some people, because of their genetic background, metabolize dietary isothiocyanates differently. However, research has not yet revealed a specific group of people who, because of their genetics, benefit more than other people from eating cruciferous vegetables.

The evidence has been reviewed by various experts 48). Key studies regarding four common forms of cancer are described briefly below.

  • Prostate cancer: Cohort studies in the Netherlands 49), United States 50), and Europe 51) have examined a wide range of daily cruciferous vegetable intakes and found little or no association with prostate cancer risk. However, some case-control studies have found that people who ate greater amounts of cruciferous vegetables had a lower risk of prostate cancer 52), 53).
  • Colorectal cancer: Cohort studies in the United States and the Netherlands have generally found no association between cruciferous vegetable intake and colorectal cancer risk 54), 55), 56). The exception is one study in the Netherlands—the Netherlands Cohort Study on Diet and Cancer—in which women (but not men) who had a high intake of cruciferous vegetables had a reduced risk of colon (but not rectal) cancer 57).
  • Lung cancer: Cohort studies in Europe, the Netherlands, and the United States have had varying results 58), 59), 60). Most studies have reported little association, but one U.S. analysis—using data from the Nurses’ Health Study and the Health Professionals’ Follow-up Study—showed that women who ate more than 5 servings of cruciferous vegetables per week had a lower risk of lung cancer 61).
  • Breast cancer: One case-control study found that women who ate greater amounts of cruciferous vegetables had a lower risk of breast cancer 62). A meta-analysis of studies conducted in the United States, Canada, Sweden, and the Netherlands found no association between cruciferous vegetable intake and breast cancer risk 63). An additional cohort study of women in the United States similarly showed only a weak association with breast cancer risk 64).

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