Focus on Nutrition Concerns of
Young Women

Through adolescence into their early twenties, young women undergo dramatic changes, including physical, social, cognitive, and emotional development. At a time when nutrient requirements peak, the lifestyles of young women may compromise their food intake placing them at risk for a multitude of nutritional imbalances. Lack of research on the nutritional status of young Canadian women, combined with wide individual variability in biological makeup and lifestyle practices within this age group, make it difficult to paint a clear picture of their nutritional health. Most attention directed to this age group tends to be on issues of weight including obesity, dysfunctional eating, and eating disorders. While these are important, this emphasis does not capture the full spectrum of nutritional health concerns facing young women today. Dietary deficiencies -- most notably iron, calcium, and folate -- are commonly related to inadequate energy intakes or the omission of whole food groups. This article highlights current knowledge about the nutritional health of young Canadian females, profiles trends in their eating patterns, and suggests how family practitioners can support their clients in achieving and maintaining nutritional health.

Nutritional Health and Dietary Intake

Young women are particularly susceptible to compromised dietary intakes and poor nutritional health. A recent survey of the food consumption patterns of Canadian adults (18-65 years) and adolescents (13-17 years) revealed a far from stellar performance by females.¹ While energy and fat intakes were close to current recommendations, a significant number of young women were reported to consume inadequate intakes of calcium, folate and iron - nutrients of critical importance during their reproductive years. Mean fat intake was reported to be comparable to the recommended intake of no more than 30% of total energy as fat for both age groups. When their diets were compared with Canada's Food Guide to Healthy Eating, however, younger females had marginal or below recommended intakes for fruits and vegetables, meat and alternates, milk and milk products, and grains.² Moreover, foods not considered part of the four food groups accounted for 27-29 % of total energy and 29-32 % of total fat intake in the diets of both age groups. Extra foods included soft drinks and fruit drinks (not juices), desserts, candy, ice cream bars, potato chips, oils, spreads, and similar foods - all of which tend to be high in energy but not nutrient dense.

The escalating problem of overweight and obesity is a priority health issue among young women. The prevalence of overweight among girls aged 7-13 years increased from 15% to 23.6% between 1981 and 1996, while the prevalence of obesity more than doubled, from 5% to 11.8%.³ Consistent with these trends, the proportion of female students in grades 6-10 who report that they exercise two or more times a week outside of school hours declined between 1990 and 1998.⁴ Overweight adolescents are not only at increased risk for obesity-associated chronic diseases but the cycle of emotional and socio-economic problems associated with obesity as well. The dismal success rate of weight-loss programs points to the importance of prevention. However, focusing on dietary restraint is clearly not the answer, given its link with the growing prevalence of eating disorders including bulimia nervosa and anorexia nervosa.⁵ Although Caucasian females and athletes are at higher risk of eating disorders, all young women are vulnerable to society's pressure to be thin and the emphasis on dieting.⁶ Almost half of girls in grades 9 and 10 reported that they were either on a diet or needed to lose weight.⁷

Iron deficiency is the most common nutrient deficiency among older adolescent girls and young women due to iron losses during menses and poor dietary intakes. Compared with other age groups, female teens have the highest requirements for dietary iron but the lowest intakes.⁸ It is estimated that between 29 and 84% of young Canadian women may not meet the Recommended Nutrient Intake (RNI) for iron.⁹ The consequences of iron deficiency are subtle but serious, including decreased work performance, impaired body temperature regulation, and altered intellectual performance.^5,10

Although the prevalence of calcium deficiency among young Canadian women is unknown, concern about their calcium intake has increased because of its association with bone health in later years. Maximizing peak bone mass during the first two to three decades of life can prevent osteoporosis. Dietary calcium improves bone accretion, but 60% of females aged 13-17 years are reported to consume less than the recommended intake of milk and milk products, the best source of calcium.² Vitamin D is needed along with calcium to build strong bones while excess sodium, protein, caffeine, and phosphorus may compromise bone health. The displacement of milk by soft drinks is common among young women.¹² This practice not only displaces the nutrients from milk, but also impairs calcium absorption due to the high phosphorus content of soft drinks.⁶

Another key nutrition concern, reported in both the United States¹³ and Canada² relates to the inadequate consumption of fruits and vegetables among adolescents. In particular, young women from low socio-economic backgrounds and those with limited family connectedness tend to have low consumption of fruits and vegetables.¹³ Fruits and vegetables are sources of key vitamins, such as folate, which is linked to the prevention of neuro-tube defects in offspring, and heart disease and cancer in later life.¹⁴ The antioxidant and photochemical content of fruits and vegetables also have a role in preventing heart disease and cancer.⁵ Consuming fruits and vegetables daily with particular attention to adequate folate intake should be a nutritional priority for young women.

Trends in Eating Patterns

Current lifestyle trends can influence the nutritional adequacy of women's diets. Less structured eating, with a shift in food consumption from meals to snacks, is common among young adults,¹⁵ yet the nutritional consequences are unclear. High energy snack foods and supersizing portions of popular foods promote overeating and energy imbalance and can contribute to obesity. With wise choices, however, snacking can significantly boost the daily nutrient intake of young women. Dwyer reported that as the number of eating occasions increased, mean intakes of energy, total carbohydrates and sugar increased.¹⁶ Breakfasts and snacks, compared with lunches and dinners, tended to be lower in total and saturated fat but higher in sugar and total carbohydrate as a percentage of total energy intakes. Eating away from home is common among young women but American data suggests that the iron density of away-from-home foods is significantly lower than food consumed at home.⁸

In her study of American adolescents, Dwyer also found that overweight students were more likely to skip breakfast, eat fewer than two meals a day, and consequently have lower energy intakes than their peers.¹⁶ Breakfasts make a significant contribution to iron intake, especially when iron fortified cereals are eaten. Results of a survey of college and university students in Vancouver revealed that only 54% of male and female students reported always eating breakfast while 34% said they usually did, despite acknowledging that eating breakfast benefited their work performance.¹⁷ Family food purchasing patterns, food costs, and storage and cooking facilities were the main factors influencing breakfast choices.

Increasing numbers of young women are shifting to various patterns of vegetarian eating. Some omit only red meats; others restrict flesh foods but not eggs or dairy products; and vegans avoid all foods of animal origin. One in five Canadian teen girls reported not consuming any meats or alternates and a further 35.5% consumed less than the recommended 2 servings/day.2 The more limited one's intake of animal foods the greater the likelihood of nutrient inadequacy, with protein, iron, calcium, vitamins D and B₁₂ being of particular concern. To compensate for less biologically available iron in a plant-based diet, vegetarians need to consume twice as much iron as meat eaters and combine these non-heme sources with foods rich in vitamin C. Because vitamin B₁₂ is only found in animal foods, vegans must include foods fortified with vitamin B₁₂ or look to supplements.

Nevertheless, vegetarians who are well informed and motivated can achieve a healthy diet. A comparison of nutrient intakes of health-conscious female vegetarians and non-vegetarians in British Columbia found few differences in nutrient intakes.¹⁸ Although some have suggested that menstrual irregularities are more common among vegetarians,¹⁹ Barr and colleagues found that healthy vegetarian women experienced fewer menstrual disturbances than did non-vegetarians.²⁰

What Can Family Practitioners Do?

The nutrition concerns of young women has become of increasing interest to family practitioners as evidence accumulates supporting the role of diet in women's health. Adolescents report that health care providers and clinics, along with parents, friends and magazines, are their most valuable sources of information for diet, nutrition and exercise concerns.²¹

Practitioners must consider all factors that shape their client's health, such as income and social status, education, social support networks, culture, health practices and personal coping mechanisms. Canadians 15-24 years of age are increasingly limited to low paying jobs resulting in a 38% decline in their average earnings between 1980 and 1995²² and increased potential for long hours of work. Both trends have been related to deficits in nutrition as well as other risk factors for poor health.^23,24 Stress relief and weight-control have been reported as primary reasons for teenage girls to take up smoking, a habit that not only compromises nutritional status but also has serious health consequences.²⁵

Gender itself is a determinant of health with diverse factors in the lives of young women having the potential to either support or compromise nutrition. Surveys of Canadian women have consistently shown that women are more likely than men to consider nutrition important and to take action to improve their diet.²⁶ Many are searching for credible information in a maze of misinformation and look to their primary health providers for guidance. As the key decision-makers about food choices for their families, women's commitment to healthy eating influences more than their own health. Young women are prime targets for nutrition intervention.

• Promote the prevention of obesity through healthy lifestyle practices including physical activity, healthy eating and positive self-esteem. Avoid recommending restrictive dieting - a practice that has a dismal success rate and can trigger dysfunctional eating behaviour.
• Identify young women who may be especially vulnerable to low intakes of calcium, iron and folate, especially if they routinely limit the quantity or variety of food eaten.
• Encourage young women to include in their daily eating pattern:
  • At least 3 servings of low fat milk and milk products as a source of calcium - a must for bone health.
  • At least five servings of fruits and vegetables per day.
  • Two to three servings of meat or alternates a day.
  • Five or more servings of grain products depending on energy requirements.
• Direct vegetarians to reliable and practical information on healthy vegetarian eating. Special attention needs to be placed on incorporating iron, combined with a good source of vitamin C, and calcium rich foods into the plant-based diet. Vegans should include dietary sources of vitamin B₁₂ such as B₁₂-fortified soy or rice beverages and fortified cereals, or a vitamin B₁₂ supplement.
• Recognize that lifestyles at this age are likely to result in erratic eating patterns. Encourage young women to have nutritious foods available for on-the-run meals and snacks, and to make wise food choices when eating away from home.
• Focus on healthy eating practices and recommend appropriate vitamin-mineral supplements to those young women who are unable to select foods that provide a nutritionally adequate diet. Supplements, however, can never replace healthy eating.
• Begin by considering the issues important to the health and lifestyles of young women and seek their input in making recommendations for improving their eating practices.

Doris E. Gillis, Patricia Williams

References:

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19. Pederson, AB, Bartholomew, MJ, Dolence, LA, Aljadir, LP, Netteburg, KL, Lloyd,T. Menstrual differences due to vegetarian and non-vegetarian diets. Am J Clin Nutr 1991;53:879-85.
     
20. Barr, S, Janelle, C, Prior, JC. Vegetarian vs nonvegetraian diets, dietary restraint,, and subclinical ovulatory disturbances: Prospective 6-mo study. Am J Clin Nutr, 1994;60:887-94.
     
21. Borzekowski, DLG, Rickert, VI. Adolescent cybersurfing for health information: A new resource that crosses barriers. Arch Pediatr Adolesc Med 2001;155:813-817.
     
22. Statistics Canada. The Daily: Tuesday May 12, 1998. Catalogue number 11-001E (Francais 11-001F) ISSN 0827-0465.
     
23. National Academy of Sciences. Protecting Youth at Work: Health, Safety and Development of Working Children and Adolescents in the United States. Washington, D.C.: National Academy Press, 1998.
     
24. Raphael, D. Inequality is Bad for Our Hearts: Why Low Income and Social Exclusion are Major Causes of Heart Disease in Canada. Toronto: North York Heart Health Network, 2001.
     
25. Coleman, R. Women's Health in Atlantic Canada: A Statistical Portrait. Maritime Centre of Excellence for Women's Health. February 2000
     
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You can search for abstracts of the above references by following this link: PubMed