|Posted by MSRD on October 9, 2010 at 1:09 PM|
By Grace Lam
Recently, the importance of breakfast consumption has received a lot of attention. Breakfast is the first meal of the day usually eaten within 2 hours of waking and no later than 10:00a.m. The calorie level is usually between 20% and 35% of the total daily energy needs . Although breakfast should constitute about one-third of daily calories, the percentage of Americans who consume breakfast has decreased. According to the National Health and Nutrition Examination Survey (NHANES) What We Eat in America (WWEIA) 2007-2008 , only 80% of Americans ate breakfast on any given day. The percentages were much lower for some groups, such as adolescents and young adults (~70%). As skipping breakfast has become increasingly common in the United States, many studies have been done to examine the adverse effects of omitting breakfast on quality of life (QOL) .Skipping breakfast has been linked to reduced cognitive function , poorer academic performance , worsened mood and increased fatigue in adolescents. Studies have also shown that missing breakfast has similar detrimental effects on young adults. The purpose of this paper is to review the effect of skipping breakfast on body weight, insulin sensitivity, fasting lipid profile, and menstrual cycle in healthy adolescents and young adults between 13 and 25 years old.
The role of breakfast in weight control is still inconclusive. Most adolescents and young adults think that skipping breakfast is a good strategy to lose weight because it can decrease energy intake. Nicklas’s study reported that breakfast skippers had significantly lower caloric and protein intakes than individuals who eat breakfast. A study conducted by Berkey et al. supported that adolescents who skip breakfast have significantly lower energy intake than those who eat breakfast (P<0.0001, adjusted for age, Tanner stage, race, menarche, physical activity and inactivity). However, Halsey et al.’s study showed that there is no significant difference in total energy intake between breakfast skippers and breakfast eaters. Also there is no significant difference in the frequency of food intake between breakfast skippers and breakfast eaters throughout the day.
On the other hand, Leidy et al.’s study showed that skipping breakfast is actually associated with increased appetite and increased body weight in adolescents. The result obtained from the Third National Health and Nutrition Examination Survey (NHANES III) also showed that adolescents and young adults who skip breakfast have significantly higher BMI than those who eat breakfast.
Other findings from the Seasonal Variation of Blood Cholesterol Study supported the adverse effect of skipping breakfast on body weight. The study showed that skipping breakfast is associated with a significantly higher risk of obesity. Non-institutionalized healthy adults (20 to 70 years old) who regularly skipped breakfast (more than 75% of the time during the study) had 4.5 times the risk of obesity than those who regularly consumed breakfast. Non-institutionalized healthy adults who skipped breakfast at least once during the study had 1.34 times the risk of obesity than those who always consumed breakfast.
Although there is no established causal relationship between the omission of breakfast and weight gain, the above studies suggest an association between skipping breakfast and weight gain. As a result, skipping breakfast might not be an effective weight loss technique. According to Martin et al. , the result of increased body weight in breakfast eaters mentioned in Berkey et al. and Nicklas’s studies could possibly be due to a larger portion size eaten during breakfast time, or higher calorie food being chosen during breakfast time.
The study that examined the data obtained from NHANES III 12 showed that those who consumed high-calorie food, such as meat and eggs, during breakfast usually have a significantly higher BMI compare to those who consumed low-calorie food, such as cereal, during breakfast.In conclusion, skipping breakfast and choosing high-energy food as breakfast are associated with increased BMI in adolescents and young adults.
Most of the studies have focused on children and limited studies have investigated the effect of skipping breakfast on the blood glucose levels of adolescents and young adults. As a result, Farshchi et al. conducted a study on a group of healthy young adults who omit breakfast most day of the week.
In Farshchi et al.’s study, a group of healthy young women with normal body weight were recruited to examine the effect of skipping breakfast on circulating blood glucose level and insulin sensitivity. The subjects were asked to eat bran flakes with low-fat milk before 8:00 a.m. for two weeks, and to eat lunch and dinner at their normal mealtimes. They were also allowed to consume two snacks during the day. After a two-week break, the group then changed their schedule and skipped breakfast. They were told to eat their first meal of the day between noon and 1:30 p.m. After the first meal, they were allowed to eat two additional meals and two snacks as well. Both diets allowed a cookie between 10:30 and 11:00 in the morning. Although the study showed that the blood glucose level remained constant over time, the peak postprandial insulin response tended to be significantly lower after the “eating breakfast (EB) period” than after the “omitting breakfast (OB) period.” Thus the authors suggested that skipping breakfast may only reduce postprandial but not fasting insulin sensitivity in young healthy adults. The reason why omitting breakfast led to reduced postprandial insulin sensitivity is not clear.
In a cross-sectional study conducted by Alexander et al. , the researchers also showed that skipping breakfast does not affect the insulin sensitivity and beta-cell function in healthy adolescents. In this study, the researchers divided a group of Latino adolescents into three groups. Although they were overweight and had a positive family history of type-2-diabetes, they were physically healthy. The participants in the first group were those who did not eat breakfast at all; the second group included those who ate breakfast one or two days a week, and the third group included those who ate breakfast everyday. When insulin sensitivity, acute insulin response and beta-cell function were tested, the results showed that there were no significant differences among the three groups. According to Farshchi et al., during short-term interventions in healthy adolescents, blood glucose is likely to remain constant, and any compensation would occur via changes in insulin secretion.
In conclusion, even though the results of the above studies showed that skipping breakfast does not affect the glucose profile in the healthy individual, they suggested that this altered eating habit can affect the body’s response to insulin and result in insulin resistance over a long period of time.
Fasting Lipid Profiles
Lipid disorders are very common in the United States. Data from the Behavioral Risk Factor Surveillance System 2009 showed that 9.1% of U.S. adolescents and young adults, 18 to 24 years old, had been told that they have high blood lipid levels . Certain patterns of blood lipids, including elevated total cholesterol (TC), elevated low-density lipoprotein cholesterol (LDL), and low levels of high-density lipoprotein (HDL) cholesterol, are important risk factors for coronary heart disease (CHD) . A limited number of studies have investigated the effect of omitting breakfast on total fat consumption and serum lipid concentrations.
Farshchi et al. compared the changes in the lipid profiles of a group of healthy young women and the effect of skipping breakfast on their lipid profile. The results indicated that the plasma TC did not change significantly after the eating breakfast (EB) period but increased significantly after the omitting breakfast (OB) period. The plasma LDL concentration also rose significantly after the OB period but did not change significantly after the EB period. However, no significant differences were observed in plasma HDL concentration over either period. Plasma triacylglycerol concentrations also showed no significant difference over the course of the experiment. Farshchi et al concluded that omitting breakfast is associated with higher plasma lipid concentrations. Although the mechanism is not clear, they assumed that higher total and LDL-cholesterol concentrations after the OB period is due to the increased insulin stimulation of a cholesterol synthesis enzyme, hydroxyl methyl glutaryl-Co-A reductase. This study suggested that skipping breakfast can elevate the total cholesterol and the plasma LDL in a young healthy adult, which increases the risk of developing coronary heart disease.
In addition to body weight, insulin sensitivity, fasting lipid profiles, dysmennorrhea may also be associated with skipping breakfast. According to Slap , dysmenorrhoea is the most common symptom of menstrual disorders, which affects approximately 50% of menstruating women. Dysmenorrhoea is the cyclic menstruation pain in the lower abdomen, which usually is associated with other gastrointestinal and neurological symptoms. The pain is thought to be caused by the uterine contractions and ischemia which is mediated by the production of prostaglandins in the secretory endometrium.
One of the studies conducted by Montero et al. has shown that an inadequate nutritional state can induce dysfunction in the hypothalamic-pituitary-ovarian axis. As skipping breakfast might limit nutrient intake, this can significantly decrease young women’s diet quality and their nutritional status, which in turn results in dysmenorrhea .
Although the symptoms can be caused by the hormonal changes of the body, such as gonadotropins or ovarian sex steroid hormones, Fujiwara’s study has shown that young women who skip breakfast have a significantly higher degree of dysmenorrhea symptoms compared with those young women who eat breakfast.
In Fujiwara’s study, a group of young women, 18 to 20 years old, were divided into three groups. The first group was assigned to have breakfast every morning. The second group was assigned to have breakfast only several (1-6) times per week. The third group was assigned to have one breakfast per week or they were assigned to skip their breakfasts all togehter. When the three groups of young women were compared, the intensity of dysmenorrhea of the second group and the third group scored significantly higher than the first group. Although there was no explanation for the cause of dysmenorrhea in the young women who skipped breakfast, Fujiwara hypothesized that omitting breakfast, which can result in the deficiency of some nutrients, can lead to the development of an organic gynecological disorder called endometriosis.
Although endometriosis is mostly explained by Sampson’s retrograde menstruation theory , the presence of dysmenorrhea can also indicate endometriosis. Fujiwara’s study showed that there was relationship between skipping breakfast and dysmenorrhea, which can increase the risk of developing endometriosis. Another study conducted several years later by Fujiwara and his colleagues also indicated a close relationship between skipping breakfast and dysmenorrhea. This study again showed that the rate of reporting dysmenorrhea in the breakfast skipping group was significantly higher than that in the breakfast eating group (43% vs 57%, p<0.05), which was consistent with the previous study. A five-year longitudinal survey was conducted between 2004 and 2008 and confirmed the findings of the above studies as well. This study not only showed that young women who skipped breakfast have a significantly higher degree of dysmenorrhea, it also suggested that skipping breakfast can result in altered ovarian function such as endometriosis.
Much evidence has shown that skipping breakfast is harmful to health. More and more researchers have suggested that skipping breakfast can affect adolescents and young adults’ body weight, insulin sensitivity, lipid profile and reproductive functions. Due to the misconception of increasing energy intake by eating breakfast, adolescents and young adults are more likely to skip breakfast because of dieting. However, the long-term effects of skipping breakfast can be detrimental. It is necessary for the public health professional to promote regular breakfast consumption, especially in the population between 13 to 25 years old.