Benutzerspezifische Werkzeuge

Information zum Seitenaufbau und Sprungmarken fuer Screenreader-Benutzer: Ganz oben links auf jeder Seite befindet sich das Logo der JLU, verlinkt mit der Startseite. Neben dem Logo kann sich rechts daneben das Bannerbild anschließen. Rechts daneben kann sich ein weiteres Bild/Schriftzug befinden. Es folgt die Suche. Unterhalb dieser oberen Leiste schliesst sich die Hauptnavigation an. Unterhalb der Hauptnavigation befindet sich der Inhaltsbereich. Die Feinnavigation findet sich - sofern vorhanden - in der linken Spalte. In der rechten Spalte finden Sie ueblicherweise Kontaktdaten. Als Abschluss der Seite findet sich die Brotkrumennavigation und im Fussbereich Links zu Barrierefreiheit, Impressum, Hilfe und das Login fuer Redakteure. Barrierefreiheit JLU - Logo, Link zur Startseite der JLU-Gießen Direkt zur Navigation vertikale linke Navigationsleiste vor Sie sind hier Direkt zum Inhalt vor rechter Kolumne mit zusaetzlichen Informationen vor Suche vor Fußbereich mit Impressum

Artikelaktionen

Nutrient intake and nutritional status of vegetarians and low-meat eaters consuming a diet meeting preventative recommendations

I. Hoffmann, M. J. Groeneveld, C. Leitzmann

Poster auf dem Third International Congress on Vegetarian Nutrition,
Loma Linda, California, USA, März 1997

 

Introduction

The dietary recommendations for the prevention of nutrition-related diseases are based on a high consumption of vegetables (including potatoes), fruits, whole grain products and dairy products and on a reduced consumption of meat and meat products. In the general population there is a growing readiness to change the diet in the direction for the prevention of the so-called western diseases. Those single general recommendations derived from international research need to be converted into a daily diet which can easily be followed. This diet should provide a sufficient intake of all essential nutrients, a high intake of protective nutrients and a minimal intake of risk factors. Since the recommendations taken together as a healthy diet can be practiced in different forms - e.g. different amounts of meat and meat products may be included - the effect on the nutritional and health status needed to be investigated.

Objective

The underlying concept was to reveal potential weaknesses and strengths of different diets which convert all preventative recommendations at the same time.The goal of this study was to investigate the effect of different translations of international recommendations (including different amounts of meat) on the overall nutrient intake and nutritional status of healthy women. Of further interest was the comparison to a corresponding group of women eating an average mixed diet.

Methods

Study design: cross sectional study with healthy women aged 25-65 years
Group A:

111 vegetarians (VEG), food selection as internationally recommended, omitting meat and fish from their diet

Group B: 132 low-meat eaters (LME), same as Group A, but including small amounts of meat (about 30 g/d on average)
Group C: 175 women (control group) eating a normal mixed diet containing about 130 g meat/d
Recruitment:

nationwide by advertisements in journals and magazines, selection for further participation on the basis of a semiquantitative food frequency list

Instruments:

7-day estimated food record (validated for this study) two questionnaires (including food frequency list)

Blood samples: single measurement, fasting blood sample
 

Results

Study group

Table 1 lists the descriptive characteristics of the three study groups.

 

Food consumption

The analysis of the 7-day estimated food records showed that the food consumption of the three groups varied significantly for almost all foods (Table 2). The VEG and LME consumed mainly whole grain products instead of highly processed grain products, i.e. whole grain bread instead of white bread, brown rice instead of white rice, etc. Vegetables and fruits were eaten in much larger quantities than in the control group, especially in the raw form. While VEG completely omitted meat, meat products and fish from their diet, the LME consumed about 1 portion meat per week and 1 portion fish every ten days (control group: 4 portions and 1 portion per week, respectively).

It is noteworthy that the VEG did not replace meat with other animal foods - they even drank less milk and ate less dairy products and eggs than the LME.


Nutrient intake

A   Essential nutrients 

The vitamin intake as well as the corresponding plasma concentrations reflected the high consumption of plant foods of the LME and still more of the VEG (Table 3). Especially the intake of vitamins dominant in plant foods like vitamin B1, B6, folic acid, vitamin C and E was high. The intake of vitamins mainly provided by animal foods (especially vitamin B2, B12, and D) was lowest for VEG but also lower for the LME than for the control group.

Critical plasma values were only detected for vitamin B12 (Table 4). The VEG had about half of the intake of the LME and were above the RDAs of 2 µg/d. The control group had a two and a half fold intake of the recommendations. The plasma concentrations reflected the intake of vitamin B12: the control group had the highest, the VEG the lowest plasma levels. Of the LME and control group 2 %, compared to 20 % of the VEG showed plasma concentrations below the critical level of 136 pg/ml. None of the participants had vitamin B12 deficiencies like megaloblastic anemia. They may have a risk of neurological damages due to vitamin B12 deficiency but this was not investigated. However, those VEG who consumed more than 380 g dairy products per day had a satisfactory vitamin B12 status.

The VEG and LME had an overall higher intake of iron than the control group but this intake is mainly derived from plant foods from which the absorption is lower than from animal foods. For hemoglobin and plasma iron only very few women had values below the normal range. But ferritin - which reflects the iron stores - revealed that 33 % of the VEG, 21 % of the LME and 8 % of the control group were below the critical level of 17 ng/ml which means that they had depleted stores. In normal situations this is not critical, but in situations with higher iron needs (like blood loss or pregnancy) this may cause problems.

B Risk factors

The VEG had the lowest intake of substances known to be unfavorable, e.g. total fat, saturated fatty acids, cholesterol, alcohol (Figure 1). Fat intake was still too high, but lower fat intake conflicts with sufficient intake of other nutrients.The examination of blood lipids revealed that - taking other influencing factors like BMI, physical activity, age, intake of sex hormones, alcohol consumption, socio-economic status (all were non-smokers) into account - the HDL level and the LDL/HDL-ratio of the VEG and LME was higher, the triglyceride level of the VEG lower than that of the control group. No significant differences could be found for total cholesterol and LDL-cholesterol and no differences were detected between VEG and LME for all blood lipids.

C Protective nutrients

The VEG clearly showed the highest intake of protective nutrients e.g. complex carbohydrates, antioxidants, dietary fiber (Figure 2). Looking at the combined plasma level of antioxidant vitamins and b -carotene into one index (called CIAVIT) it was highest for VEG and lowest for the control group, the LME were in-between.

Because of the high intake of plant foods the VEG showed the most favorable nutrient ratio of the study groups (Figure 3). They had the highest intake of carbohydrates and the lowest intake of protein, fat and alcohol. The comparison with the recommended nutrient ratio reveals two important aspects:

  • Even though the nutrient ratio was best for the VEG on average the intake of fat was higher than internationally recommended. A subgroup of VEG which had a fat intake according to the recommendations, however, showed low vitamin B12 and vitamin D intakes and low vitamin B12 plasma concentrations.
  • The protein intake of the VEG (13 energy%) was within the internationally recommended range of 10-15 %. This means that with this type of vegetarian diet there is no risk of a protein deficiency.

Conclusions

  1. The VEG are those with the highest intake of protective factors and at the same time the lowest intake of risk factors. From the corresponding blood concentrations it may be assumed that the VEG and LME experience a lower risk of nutrition related diseases such as cancer and coronary heart diseases.
  2. At the same time, for the VEG the intake and status of some essential nutrients may be critical. To avoid potential weaknesses even for this type of vegetarian diet careful planning is necessary.
  3. A diet meeting the preventative recommendations which includes small amounts of meat retains the advantages of a vegetarian diet but avoids its possible disadvantages.
  4. The observed nutrient ratios give rise to two questions:
    Is the recommended nutrient ratio feasible with the western type diet?
    If so, can an optimal intake of all other nutrients be guaranteed?
 

Table 1: Descriptive characteristics of the study groups*

 

vegetarians

low-meat eaters

control group

 

n = 111

n = 132

n = 175

age (yrs)

43.5 + 10.6

46.1 + 10.8

42.4 + 10.3

weight (kg)

59.0 + 8.4

60.4 + 10.3

66.8 + 12.5

height (cm)

164 + 5.6

165 + 6.1

165 + 6.4

BMI (wt/ht2)

21.8 + 2.8

22.1 + 3.2

24.6 + 4.1

Mean + SD

 

Table 2: Mean food consumption (in g/d)*


vegetarians low-meat eaters control group
l n = 111 n = 132 n = 175
bread and pastries, tota 181 + 71.1 182 + 73.1 186 + 64.7
- whole grain products 162 + 70.3 149 + 65.9 48.1 + 38.8
- from refined flour 19.7 + 27.5 33.3 + 32.9 138 + 66.3
vegetables, legumes 405 + 164 349 + 163 224 + 124
- raw vegetables 247 + 112 198 + 110 92.2 + 69.8
fruits 395 + 214 339 + 155 201 + 122
- raw fruits 368 + 210 310 + 153 177 + 116
meat/meat products 0.0 + 0.0 28.8 + 28.8 137 + 55.7
fish/fish products 0.0 + 0.0 15.6 + 20.9 21.3 + 22.1
milk/dairy products 217 + 196 262 + 171 267 + 239
eggs 7.7 + 9.0 12.8 + 10.0 16.2 + 14.4
coffee, black tea 240 + 279 350 + 270 517 + 273
alcoholic beverages 39.5 + 61.0 67.3 + 88.0 120 + 128
Mean + SD

xxx highest consumption of the three study groups

 

 

Table3: Daily nutrient intake of essential nutrients*

  vegetarians low-meat eaters control group
  (n = 111) (n = 132) (n = 175)

dominant in plant foods

vitamin B1(mg) 1.8
(1.0-3.2)
1.7
(1.0-3.3)
1.3
(0.9-2.5)
vitamin B6 (mg) 2.2
(1.5-3.2)
2.2
(1.6-3.4)
1.9
(1.2-3.6)
vitamin E (mg TE) 16.9
(9.3-26.6)
15.1
(10.3-25.7)
10.7
(6.1-20.7)
vitamin C (mg) 145
(69-269)
132
(74-227)
100
(55-227)
folic acid (µg) 323
(206-505)
292
(205-454)
223
(147-540)

dominant in animal foods

vitamin B2 (mg) 1.5
(1.0-2.5)
1.6
(1.1-2.7)
1.7
(1.1-3.2)
vitamin B12(µg) 1.6
(0.2-4.2)
3.0
(1.4-6.0)
5.6
(2.9-11.7)
vitamin D (µg) 1.1
(0.4-2.7)
1.8
(0.8-5.4)
2.4
(0.9-6.1)
iron (mg)


- from plant sources

- from animal sources

 

20.7
(14.1-27.3)

18.7
(11.6-25.3)

0.5
(0.0-1.2)

19.7
(14.8-28.0)

16.7
(11.3-25.3)

1.4
(0.6-3.0)

17.1
(11.5-25.1)

11.3
(6.9-17.4)

3.7
(2.0-6.4)

* median (5-95th percentile)

xxx highest intake of the three study groups

 

Table 4: Biochemical indices of the three study groups *

  vegetarians low-meat eaters control group
  (n = 111) (n = 132) (n = 175)
vitamin B12(pmol/L) 167
(63-494)
219
(107-474)
272
(122-577)
folic acid (nmol/L) 17.9
(11.1-34.9)
18.4
(10.9-34.9)
15.4
(10.2-30.6)
iron (µmol/L) 15.9
(10.5-22.1)
16.8
(11.4-23.0)
16.6
(12.4-22.4)
ferritin (µg/L) 22
(6-70)
27
(8-90)
53
(12-180)
transferrin (µmol/L) 36.6
(25.2-49.4)
34.7
(25.5-46.6)
33.1
(24.7-42.3)
transferrin saturation (%) 23.1
(10.8-35.7)
25.4
(14.2-38.0)
25.9
(17.0-37.6)
hemoglobin (mmol/L) 2.07
(1.69-2.30)
2.08
(1.79-2.28)
2.19
(1.88-2.38)
* median (5-95th percentile)

xxx highest value of the three study groups

 

.

Fig1

 

        Fig2

 

                    Fig3